linux/tools/perf/Documentation/perf-stat.txt

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perf-stat(1)
============
NAME
----
perf-stat - Run a command and gather performance counter statistics
SYNOPSIS
--------
[verse]
'perf stat' [-e <EVENT> | --event=EVENT] [-a] <command>
'perf stat' [-e <EVENT> | --event=EVENT] [-a] -- <command> [<options>]
perf stat record: Add record command Add 'perf stat record' command support. It creates simple (header only) perf.data file ATM. The record command could be specified anywhere among stat options. All stat command options are valid for stat record command with '-o' option exception. If specified for record command it denotes the perf data file name. Committer note: Set sample_type to PERF_SAMPLE_IDENTIFIER, which should be harmless while avoiding that older tools show confusing messages, for instance, with sample_type = 0, we get: $ perf stat record usleep 1 Performance counter stats for 'usleep 1': 0.630237 task-clock (msec) # 0.528 CPUs utilized 1 context-switches # 0.002 M/sec 0 cpu-migrations # 0.000 K/sec 52 page-faults # 0.083 M/sec 978,312 cycles # 1.552 GHz 671,931 stalled-cycles-frontend # 68.68% frontend cycles idle <not supported> stalled-cycles-backend 646,379 instructions # 0.66 insns per cycle # 1.04 stalled cycles per insn 131,046 branches # 207.931 M/sec 7,073 branch-misses # 5.40% of all branches 0.001193240 seconds time elapsed $ oldperf evlist WARNING: The perf.data file's data size field is 0 which is unexpected. Was the 'perf record' command properly terminated? non matching sample_type $ While with sample_type set to PERF_SAMPLE_IDENTIFIER, after we re-run 'perf stat record usleep' we get: $ oldperf evlist WARNING: The perf.data file's data size field is 0 which is unexpected. Was the 'perf record' command properly terminated? task-clock context-switches cpu-migrations page-faults cycles stalled-cycles-frontend stalled-cycles-backend instructions branches branch-misses $ Which at least shows the names of the events in the perf.data file. Additionally, such files, when passed to 'perf report' will produce: $ oldperf report --stdio WARNING: The perf.data file's data size field is 0 which is unexpected. Was the 'perf record' command properly terminated? Warning: Kernel address maps (/proc/{kallsyms,modules}) were restricted. Check /proc/sys/kernel/kptr_restrict before running 'perf record'. As no suitable kallsyms nor vmlinux was found, kernel samples can't be resolved. Samples in kernel modules can't be resolved as well. Error: The perf.data file has no samples! # To display the perf.data header info, please use --header/--header-only options. # $ Which is confusing and can be solved by just adding the kernel mmap record, which will also remove that warning about the data size field being equal to zero, after generating the mmap record: $ perf stat record usleep 1 Performance counter stats for 'usleep 1': 0.600796 task-clock (msec) # 0.478 CPUs utilized 1 context-switches # 0.002 M/sec 0 cpu-migrations # 0.000 K/sec 54 page-faults # 0.090 M/sec 886,844 cycles # 1.476 GHz 582,169 stalled-cycles-frontend # 65.65% frontend cycles idle <not supported> stalled-cycles-backend 638,344 instructions # 0.72 insns per cycle # 0.91 stalled cycles per insn 130,204 branches # 216.719 M/sec 7,500 branch-misses # 5.76% of all branches 0.001255897 seconds time elapsed $ oldperf evlist task-clock context-switches cpu-migrations page-faults cycles stalled-cycles-frontend stalled-cycles-backend instructions branches branch-misses $ oldperf report --stdio Error: The perf.data file has no samples! # To display the perf.data header info, please use --header/--header-only options. # [acme@zoo linux]$ No warnings, sensible output about what are the events in the perf.data file and also a "file has no samples" message, which indeed it doesn't. Signed-off-by: Jiri Olsa <jolsa@kernel.org> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Tested-by: Kan Liang <kan.liang@intel.com> Cc: David Ahern <dsahern@gmail.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: htp://lkml.kernel.org/r/1446734469-11352-3-git-send-email-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-11-05 14:40:46 +00:00
'perf stat' [-e <EVENT> | --event=EVENT] [-a] record [-o file] -- <command> [<options>]
'perf stat' report [-i file]
DESCRIPTION
-----------
This command runs a command and gathers performance counter statistics
from it.
OPTIONS
-------
<command>...::
Any command you can specify in a shell.
perf stat record: Add record command Add 'perf stat record' command support. It creates simple (header only) perf.data file ATM. The record command could be specified anywhere among stat options. All stat command options are valid for stat record command with '-o' option exception. If specified for record command it denotes the perf data file name. Committer note: Set sample_type to PERF_SAMPLE_IDENTIFIER, which should be harmless while avoiding that older tools show confusing messages, for instance, with sample_type = 0, we get: $ perf stat record usleep 1 Performance counter stats for 'usleep 1': 0.630237 task-clock (msec) # 0.528 CPUs utilized 1 context-switches # 0.002 M/sec 0 cpu-migrations # 0.000 K/sec 52 page-faults # 0.083 M/sec 978,312 cycles # 1.552 GHz 671,931 stalled-cycles-frontend # 68.68% frontend cycles idle <not supported> stalled-cycles-backend 646,379 instructions # 0.66 insns per cycle # 1.04 stalled cycles per insn 131,046 branches # 207.931 M/sec 7,073 branch-misses # 5.40% of all branches 0.001193240 seconds time elapsed $ oldperf evlist WARNING: The perf.data file's data size field is 0 which is unexpected. Was the 'perf record' command properly terminated? non matching sample_type $ While with sample_type set to PERF_SAMPLE_IDENTIFIER, after we re-run 'perf stat record usleep' we get: $ oldperf evlist WARNING: The perf.data file's data size field is 0 which is unexpected. Was the 'perf record' command properly terminated? task-clock context-switches cpu-migrations page-faults cycles stalled-cycles-frontend stalled-cycles-backend instructions branches branch-misses $ Which at least shows the names of the events in the perf.data file. Additionally, such files, when passed to 'perf report' will produce: $ oldperf report --stdio WARNING: The perf.data file's data size field is 0 which is unexpected. Was the 'perf record' command properly terminated? Warning: Kernel address maps (/proc/{kallsyms,modules}) were restricted. Check /proc/sys/kernel/kptr_restrict before running 'perf record'. As no suitable kallsyms nor vmlinux was found, kernel samples can't be resolved. Samples in kernel modules can't be resolved as well. Error: The perf.data file has no samples! # To display the perf.data header info, please use --header/--header-only options. # $ Which is confusing and can be solved by just adding the kernel mmap record, which will also remove that warning about the data size field being equal to zero, after generating the mmap record: $ perf stat record usleep 1 Performance counter stats for 'usleep 1': 0.600796 task-clock (msec) # 0.478 CPUs utilized 1 context-switches # 0.002 M/sec 0 cpu-migrations # 0.000 K/sec 54 page-faults # 0.090 M/sec 886,844 cycles # 1.476 GHz 582,169 stalled-cycles-frontend # 65.65% frontend cycles idle <not supported> stalled-cycles-backend 638,344 instructions # 0.72 insns per cycle # 0.91 stalled cycles per insn 130,204 branches # 216.719 M/sec 7,500 branch-misses # 5.76% of all branches 0.001255897 seconds time elapsed $ oldperf evlist task-clock context-switches cpu-migrations page-faults cycles stalled-cycles-frontend stalled-cycles-backend instructions branches branch-misses $ oldperf report --stdio Error: The perf.data file has no samples! # To display the perf.data header info, please use --header/--header-only options. # [acme@zoo linux]$ No warnings, sensible output about what are the events in the perf.data file and also a "file has no samples" message, which indeed it doesn't. Signed-off-by: Jiri Olsa <jolsa@kernel.org> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Tested-by: Kan Liang <kan.liang@intel.com> Cc: David Ahern <dsahern@gmail.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: htp://lkml.kernel.org/r/1446734469-11352-3-git-send-email-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-11-05 14:40:46 +00:00
record::
See STAT RECORD.
report::
See STAT REPORT.
-e::
--event=::
Select the PMU event. Selection can be:
- a symbolic event name (use 'perf list' to list all events)
- a raw PMU event (eventsel+umask) in the form of rNNN where NNN is a
hexadecimal event descriptor.
- a symbolically formed event like 'pmu/param1=0x3,param2/' where
param1 and param2 are defined as formats for the PMU in
/sys/bus/event_source/devices/<pmu>/format/*
- a symbolically formed event like 'pmu/config=M,config1=N,config2=K/'
where M, N, K are numbers (in decimal, hex, octal format).
Acceptable values for each of 'config', 'config1' and 'config2'
parameters are defined by corresponding entries in
/sys/bus/event_source/devices/<pmu>/format/*
Note that the last two syntaxes support prefix and glob matching in
the PMU name to simplify creation of events across multiple instances
of the same type of PMU in large systems (e.g. memory controller PMUs).
Multiple PMU instances are typical for uncore PMUs, so the prefix
'uncore_' is also ignored when performing this match.
-i::
--no-inherit::
child tasks do not inherit counters
-p::
--pid=<pid>::
stat events on existing process id (comma separated list)
-t::
--tid=<tid>::
stat events on existing thread id (comma separated list)
-a::
--all-cpus::
system-wide collection from all CPUs (default if no target is specified)
-c::
--scale::
scale/normalize counter values
-d::
--detailed::
print more detailed statistics, can be specified up to 3 times
-d: detailed events, L1 and LLC data cache
-d -d: more detailed events, dTLB and iTLB events
-d -d -d: very detailed events, adding prefetch events
-r::
--repeat=<n>::
repeat command and print average + stddev (max: 100). 0 means forever.
perf stat: add perf stat -B to pretty print large numbers It is hard to read very large numbers so provide an option to perf stat to separate thousands using a separator. The patch leverages the locale support of stdio. You need to set your LC_NUMERIC appropriately, for instance LC_NUMERIC=en_US.UTF8. You need to pass -B to activate this feature. This way existing scripts parsing the output do not need to be changed. Here is an example. $ perf stat noploop 2 noploop for 2 seconds Performance counter stats for 'noploop 2': 1998.347031 task-clock-msecs # 0.998 CPUs 61 context-switches # 0.000 M/sec 0 CPU-migrations # 0.000 M/sec 118 page-faults # 0.000 M/sec 4,138,410,900 cycles # 2070.917 M/sec (scaled from 70.01%) 2,062,650,268 instructions # 0.498 IPC (scaled from 70.01%) 2,057,653,466 branches # 1029.678 M/sec (scaled from 70.01%) 40,267 branch-misses # 0.002 % (scaled from 30.04%) 2,055,961,348 cache-references # 1028.831 M/sec (scaled from 30.03%) 53,725 cache-misses # 0.027 M/sec (scaled from 30.02%) 2.001393933 seconds time elapsed $ perf stat -B noploop 2 noploop for 2 seconds Performance counter stats for 'noploop 2': 1998.297883 task-clock-msecs # 0.998 CPUs 59 context-switches # 0.000 M/sec 0 CPU-migrations # 0.000 M/sec 119 page-faults # 0.000 M/sec 4,131,380,160 cycles # 2067.450 M/sec (scaled from 70.01%) 2,059,096,507 instructions # 0.498 IPC (scaled from 70.01%) 2,054,681,303 branches # 1028.216 M/sec (scaled from 70.01%) 25,650 branch-misses # 0.001 % (scaled from 30.05%) 2,056,283,014 cache-references # 1029.017 M/sec (scaled from 30.03%) 47,097 cache-misses # 0.024 M/sec (scaled from 30.02%) 2.001391016 seconds time elapsed Cc: David S. Miller <davem@davemloft.net> Cc: Frédéric Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Tom Zanussi <tzanussi@gmail.com> LKML-Reference: <4bf28fe8.914ed80a.01ca.fffff5f5@mx.google.com> Signed-off-by: Stephane Eranian <eranian@google.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2010-05-18 13:00:01 +00:00
-B::
--big-num::
perf stat: add perf stat -B to pretty print large numbers It is hard to read very large numbers so provide an option to perf stat to separate thousands using a separator. The patch leverages the locale support of stdio. You need to set your LC_NUMERIC appropriately, for instance LC_NUMERIC=en_US.UTF8. You need to pass -B to activate this feature. This way existing scripts parsing the output do not need to be changed. Here is an example. $ perf stat noploop 2 noploop for 2 seconds Performance counter stats for 'noploop 2': 1998.347031 task-clock-msecs # 0.998 CPUs 61 context-switches # 0.000 M/sec 0 CPU-migrations # 0.000 M/sec 118 page-faults # 0.000 M/sec 4,138,410,900 cycles # 2070.917 M/sec (scaled from 70.01%) 2,062,650,268 instructions # 0.498 IPC (scaled from 70.01%) 2,057,653,466 branches # 1029.678 M/sec (scaled from 70.01%) 40,267 branch-misses # 0.002 % (scaled from 30.04%) 2,055,961,348 cache-references # 1028.831 M/sec (scaled from 30.03%) 53,725 cache-misses # 0.027 M/sec (scaled from 30.02%) 2.001393933 seconds time elapsed $ perf stat -B noploop 2 noploop for 2 seconds Performance counter stats for 'noploop 2': 1998.297883 task-clock-msecs # 0.998 CPUs 59 context-switches # 0.000 M/sec 0 CPU-migrations # 0.000 M/sec 119 page-faults # 0.000 M/sec 4,131,380,160 cycles # 2067.450 M/sec (scaled from 70.01%) 2,059,096,507 instructions # 0.498 IPC (scaled from 70.01%) 2,054,681,303 branches # 1028.216 M/sec (scaled from 70.01%) 25,650 branch-misses # 0.001 % (scaled from 30.05%) 2,056,283,014 cache-references # 1029.017 M/sec (scaled from 30.03%) 47,097 cache-misses # 0.024 M/sec (scaled from 30.02%) 2.001391016 seconds time elapsed Cc: David S. Miller <davem@davemloft.net> Cc: Frédéric Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Tom Zanussi <tzanussi@gmail.com> LKML-Reference: <4bf28fe8.914ed80a.01ca.fffff5f5@mx.google.com> Signed-off-by: Stephane Eranian <eranian@google.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2010-05-18 13:00:01 +00:00
print large numbers with thousands' separators according to locale
-C::
--cpu=::
Count only on the list of CPUs provided. Multiple CPUs can be provided as a
comma-separated list with no space: 0,1. Ranges of CPUs are specified with -: 0-2.
In per-thread mode, this option is ignored. The -a option is still necessary
to activate system-wide monitoring. Default is to count on all CPUs.
perf stat: Add no-aggregation mode to -a This patch adds a new -A option to perf stat. If specified then perf stat does not aggregate counts across all monitored CPUs in system-wide mode, i.e., when using -a. This option is not supported in per-thread mode. Being able to get a per-cpu breakdown is useful to detect imbalances between CPUs when running a uniform workload than spans all monitored CPUs. The second version corrects the missing cpumap[] support, so that it works when the -C option is used. The third version fixes a missing cpumap[] in print_counter() and removes a stray patch in builtin-trace.c. Examples on a 4-way system: # perf stat -a -e cycles,instructions -- sleep 1 Performance counter stats for 'sleep 1': 9592808135 cycles 3490380006 instructions # 0.364 IPC 1.001584632 seconds time elapsed # perf stat -a -A -e cycles,instructions -- sleep 1 Performance counter stats for 'sleep 1': CPU0 2398163767 cycles CPU1 2398180817 cycles CPU2 2398217115 cycles CPU3 2398247483 cycles CPU0 872282046 instructions # 0.364 IPC CPU1 873481776 instructions # 0.364 IPC CPU2 872638127 instructions # 0.364 IPC CPU3 872437789 instructions # 0.364 IPC 1.001556052 seconds time elapsed Cc: David S. Miller <davem@davemloft.net> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Robert Richter <robert.richter@amd.com> LKML-Reference: <4ce257b5.1e07e30a.7b6b.3aa9@mx.google.com> Signed-off-by: Stephane Eranian <eranian@google.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2010-11-16 09:05:01 +00:00
-A::
--no-aggr::
Do not aggregate counts across all monitored CPUs.
perf stat: Add no-aggregation mode to -a This patch adds a new -A option to perf stat. If specified then perf stat does not aggregate counts across all monitored CPUs in system-wide mode, i.e., when using -a. This option is not supported in per-thread mode. Being able to get a per-cpu breakdown is useful to detect imbalances between CPUs when running a uniform workload than spans all monitored CPUs. The second version corrects the missing cpumap[] support, so that it works when the -C option is used. The third version fixes a missing cpumap[] in print_counter() and removes a stray patch in builtin-trace.c. Examples on a 4-way system: # perf stat -a -e cycles,instructions -- sleep 1 Performance counter stats for 'sleep 1': 9592808135 cycles 3490380006 instructions # 0.364 IPC 1.001584632 seconds time elapsed # perf stat -a -A -e cycles,instructions -- sleep 1 Performance counter stats for 'sleep 1': CPU0 2398163767 cycles CPU1 2398180817 cycles CPU2 2398217115 cycles CPU3 2398247483 cycles CPU0 872282046 instructions # 0.364 IPC CPU1 873481776 instructions # 0.364 IPC CPU2 872638127 instructions # 0.364 IPC CPU3 872437789 instructions # 0.364 IPC 1.001556052 seconds time elapsed Cc: David S. Miller <davem@davemloft.net> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Robert Richter <robert.richter@amd.com> LKML-Reference: <4ce257b5.1e07e30a.7b6b.3aa9@mx.google.com> Signed-off-by: Stephane Eranian <eranian@google.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2010-11-16 09:05:01 +00:00
-n::
--null::
null run - don't start any counters
-v::
--verbose::
be more verbose (show counter open errors, etc)
perf stat: Add csv-style output This patch adds an option (-x/--field-separator) to print counts using a CSV-style output. The user can pass a custom separator. This makes it very easy to import counts directly into your favorite spreadsheet without having to write scripts. Example: $ perf stat --field-separator=, -a -- sleep 1 4009.961740,task-clock-msecs 13,context-switches 2,CPU-migrations 189,page-faults 9596385684,cycles 3493659441,instructions 872897069,branches 41562,branch-misses 22424,cache-references 1289,cache-misses Works also in non-aggregated mode: $ perf stat -x , -a -A -- sleep 1 CPU0,1002.526168,task-clock-msecs CPU1,1002.528365,task-clock-msecs CPU2,1002.523360,task-clock-msecs CPU3,1002.519878,task-clock-msecs CPU0,1,context-switches CPU1,5,context-switches CPU2,5,context-switches CPU3,6,context-switches CPU0,0,CPU-migrations CPU1,1,CPU-migrations CPU2,0,CPU-migrations CPU3,1,CPU-migrations CPU0,2,page-faults CPU1,6,page-faults CPU2,9,page-faults CPU3,174,page-faults CPU0,2399439771,cycles CPU1,2380369063,cycles CPU2,2399142710,cycles CPU3,2373161192,cycles CPU0,872900618,instructions CPU1,873030960,instructions CPU2,872714525,instructions CPU3,874460580,instructions CPU0,221556839,branches CPU1,218134342,branches CPU2,218161730,branches CPU3,218284093,branches CPU0,18556,branch-misses CPU1,1449,branch-misses CPU2,3447,branch-misses CPU3,12714,branch-misses CPU0,8330,cache-references CPU1,313844,cache-references CPU2,47993728,cache-references CPU3,826481,cache-references CPU0,272,cache-misses CPU1,5360,cache-misses CPU2,1342193,cache-misses CPU3,13992,cache-misses This second version adds the ability to name a separator and uses field-separator as the long option to be consistent with perf report. Commiter note: Since we enabled --big-num by default in 201e0b0 and -x can't be used with it, we need to notice if the user explicitely enabled or disabled -B, add code to disable big_num if the user didn't explicitely set --big_num when -x is used. Cc: David S. Miller <davem@davemloft.net> Cc: Frederik Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: paulus@samba.org Cc: Peter Zijlstra <peterz@infradead.org> Cc: Robert Richter <robert.richter@amd.com> LKML-Reference: <4cf68aa7.0fedd80a.5294.1203@mx.google.com> Signed-off-by: Stephane Eranian <eranian@google.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2010-12-01 16:49:05 +00:00
-x SEP::
--field-separator SEP::
print counts using a CSV-style output to make it easy to import directly into
spreadsheets. Columns are separated by the string specified in SEP.
--table:: Display time for each run (-r option), in a table format, e.g.:
$ perf stat --null -r 5 --table perf bench sched pipe
Performance counter stats for 'perf bench sched pipe' (5 runs):
# Table of individual measurements:
5.189 (-0.293) #
5.189 (-0.294) #
5.186 (-0.296) #
5.663 (+0.181) ##
6.186 (+0.703) ####
# Final result:
5.483 +- 0.198 seconds time elapsed ( +- 3.62% )
-G name::
--cgroup name::
monitor only in the container (cgroup) called "name". This option is available only
in per-cpu mode. The cgroup filesystem must be mounted. All threads belonging to
container "name" are monitored when they run on the monitored CPUs. Multiple cgroups
can be provided. Each cgroup is applied to the corresponding event, i.e., first cgroup
to first event, second cgroup to second event and so on. It is possible to provide
an empty cgroup (monitor all the time) using, e.g., -G foo,,bar. Cgroups must have
corresponding events, i.e., they always refer to events defined earlier on the command
line. If the user wants to track multiple events for a specific cgroup, the user can
use '-e e1 -e e2 -G foo,foo' or just use '-e e1 -e e2 -G foo'.
If wanting to monitor, say, 'cycles' for a cgroup and also for system wide, this
command line can be used: 'perf stat -e cycles -G cgroup_name -a -e cycles'.
-o file::
--output file::
Print the output into the designated file.
--append::
Append to the output file designated with the -o option. Ignored if -o is not specified.
--log-fd::
Log output to fd, instead of stderr. Complementary to --output, and mutually exclusive
with it. --append may be used here. Examples:
3>results perf stat --log-fd 3 -- $cmd
3>>results perf stat --log-fd 3 --append -- $cmd
--pre::
--post::
Pre and post measurement hooks, e.g.:
perf stat --repeat 10 --null --sync --pre 'make -s O=defconfig-build/clean' -- make -s -j64 O=defconfig-build/ bzImage
2013-01-29 11:47:44 +00:00
-I msecs::
--interval-print msecs::
Print count deltas every N milliseconds (minimum: 1ms)
perf stat: Reduce min --interval-print to 10ms The --interval-print parameter was limited to 100ms. However, for example, 10ms is required to do sophisticated bandwidth analysis using uncore events. The test shows that the overhead of the system-wide uncore monitoring with 10ms interval is only ~2%. So this patch reduces the minimal interval-print allowd to 10ms. But 10ms may not work well for all cases. For example, when the cpus/threads number is very large, for system-wide core event monitoring the overhead could be high. To handle this issue, a warning will be displayed when the interval-print is set between 10ms to 100ms. So users can make a decision according to their specific cases. # perf stat -e uncore_imc_1/cas_count_read/ -a --interval-print 10 -- sleep 1 print interval < 100ms. The overhead percentage could be high in some cases. Please proceed with caution. # time counts unit events 0.010200451 0.10 MiB uncore_imc_1/cas_count_read/ 0.020475117 0.02 MiB uncore_imc_1/cas_count_read/ 0.030692800 0.01 MiB uncore_imc_1/cas_count_read/ 0.040948161 0.02 MiB uncore_imc_1/cas_count_read/ 0.051159564 0.00 MiB uncore_imc_1/cas_count_read/ Signed-off-by: Kan Liang <kan.liang@intel.com> Acked-by: Jiri Olsa <jolsa@kernel.org> Cc: Andi Kleen <ak@linux.intel.com> Cc: Namhyung Kim <namhyung@kernel.org> Link: http://lkml.kernel.org/r/1443776674-42511-1-git-send-email-kan.liang@intel.com [ Added warning about overhead when using sub 100ms intervals to the man page ] Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-10-02 09:04:34 +00:00
The overhead percentage could be high in some cases, for instance with small, sub 100ms intervals. Use with caution.
example: 'perf stat -I 1000 -e cycles -a sleep 5'
perf stat: Add support to print counts for fixed times Introduce a new option to print counts for fixed number of times and update 'perf stat' documentation accordingly. Show below is the output of the new option for perf stat. $ perf stat -I 1000 --interval-count 2 -e cycles -a # time counts unit events 1.002827089 93,884,870 cycles 2.004231506 56,573,446 cycles We can just print the counts for several times with this newly introduced option. The usage of it is a little like 'vmstat', and it should be used together with "-I" option. $ vmstat -n 1 2 procs ---------memory-------------- --swap- ----io-- -system-- ------cpu--- r b swpd free buff cache si so bi bo in cs us sy id wa st 0 0 0 78270544 547484 51732076 0 0 0 20 1 1 1 0 99 0 0 0 0 0 78270512 547484 51732080 0 0 0 16 477 1555 0 0 100 0 0 Changes since v3: - merge interval_count check and times check to one line. - fix the wrong indent in stat.h - use stat_config.times instead of 'times' in cmd_stat function. Changes since v2: - none. Changes since v1: - change the name of the new option "times-print" to "interval-count". - keep the new option interval specifically. Signed-off-by: yuzhoujian <yuzhoujian@didichuxing.com> Acked-by: Jiri Olsa <jolsa@kernel.org> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: David Ahern <dsahern@gmail.com> Cc: Kan Liang <kan.liang@intel.com> Cc: Milian Wolff <milian.wolff@kdab.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Wang Nan <wangnan0@huawei.com> Link: http://lkml.kernel.org/r/1517217923-8302-2-git-send-email-ufo19890607@gmail.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2018-01-29 09:25:22 +00:00
--interval-count times::
Print count deltas for fixed number of times.
This option should be used together with "-I" option.
example: 'perf stat -I 1000 --interval-count 2 -e cycles -a'
--interval-clear::
Clear the screen before next interval.
perf stat: Add support to print counts after a period of time Introduce a new option to print counts after N milliseconds and update 'perf stat' documentation accordingly. Show below is the output of the new option for perf stat. $ perf stat --time 2000 -e cycles -a Performance counter stats for 'system wide': 157,260,423 cycles 2.003060766 seconds time elapsed We can print the count deltas after N milliseconds with this new introduced option. This option is not supported with "-I" option. In addition, according to Kangliang's patch(19afd10410957), the monitoring overhead for system-wide core event could be very high if the interval-print parameter was below 100ms, and the limitation value is 10ms. So the same warning will be displayed when the time is set between 10ms to 100ms, and the minimal time is limited to 10ms. Users can make a decision according to their spcific cases. Committer notes: This actually stops the workload after the specified time, then prints the counts. So I renamed the option to --timeout and updated the documentation to state that it will not just print the counts after the specified time, but will really stop the 'perf stat' session and print the counts. The rename from 'time' to 'timeout' also fixes the build in systems where 'time' is used by glibc and can't be used as a name of a variable, such as centos:5 and centos:6. Changes since v3: - none. Changes since v2: - modify the time check in __run_perf_stat func to keep some consistency with the workload case. - add the warning when the time is set between 10ms to 100ms. - add the pr_err when the time is set below 10ms. Changes since v1: - none. Signed-off-by: yuzhoujian <yuzhoujian@didichuxing.com> Acked-by: Jiri Olsa <jolsa@kernel.org> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: David Ahern <dsahern@gmail.com> Cc: Kan Liang <kan.liang@intel.com> Cc: Milian Wolff <milian.wolff@kdab.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Wang Nan <wangnan0@huawei.com> Link: http://lkml.kernel.org/r/1517217923-8302-3-git-send-email-ufo19890607@gmail.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2018-01-29 09:25:23 +00:00
--timeout msecs::
Stop the 'perf stat' session and print count deltas after N milliseconds (minimum: 10 ms).
This option is not supported with the "-I" option.
example: 'perf stat --time 2000 -e cycles -a'
perf stat: Implement --metric-only mode Add a new mode to only print metrics. Sometimes we don't care about the raw values, just want the computed metrics. This allows more compact printing, so with -I each sample is only a single line. This also allows easier plotting and processing with other tools. The main target is with using --topdown, but it also works with -T and standard perf stat. A few metrics are not supported. To avoiding having to hardcode all the metrics in the code it uses a two pass approach: first compute dummy metrics and only print the headers in the print_metric callback. Then use the callback to print the actual values. There are some additional changes in the stat printout code to handle all metrics being on a single line. One issue is that the column code doesn't know in advance what events are not supported by the CPU, and it would be hard to find out as this could change based on dynamic conditions. That causes empty columns in some cases. The output can be fairly wide, often you may need more than 80 columns. Example: % perf stat -a -I 1000 --metric-only 1.001452803 frontend cycles idle insn per cycle stalled cycles per insn branch-misses of all branches 1.001452803 158.91% 0.66 2.39 2.92% 2.002192321 180.63% 0.76 2.08 2.96% 3.003088282 150.59% 0.62 2.57 2.84% 4.004369835 196.20% 0.98 1.62 3.79% 5.005227314 231.98% 0.84 1.90 4.71% v2: Lots of updates. v3: Use slightly narrower columns v4: Add comment Signed-off-by: Andi Kleen <ak@linux.intel.com> Acked-by: Jiri Olsa <jolsa@kernel.org> Link: http://lkml.kernel.org/r/1457049458-28956-6-git-send-email-andi@firstfloor.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2016-03-03 23:57:36 +00:00
--metric-only::
Only print computed metrics. Print them in a single line.
Don't show any raw values. Not supported with --per-thread.
perf stat: Implement --metric-only mode Add a new mode to only print metrics. Sometimes we don't care about the raw values, just want the computed metrics. This allows more compact printing, so with -I each sample is only a single line. This also allows easier plotting and processing with other tools. The main target is with using --topdown, but it also works with -T and standard perf stat. A few metrics are not supported. To avoiding having to hardcode all the metrics in the code it uses a two pass approach: first compute dummy metrics and only print the headers in the print_metric callback. Then use the callback to print the actual values. There are some additional changes in the stat printout code to handle all metrics being on a single line. One issue is that the column code doesn't know in advance what events are not supported by the CPU, and it would be hard to find out as this could change based on dynamic conditions. That causes empty columns in some cases. The output can be fairly wide, often you may need more than 80 columns. Example: % perf stat -a -I 1000 --metric-only 1.001452803 frontend cycles idle insn per cycle stalled cycles per insn branch-misses of all branches 1.001452803 158.91% 0.66 2.39 2.92% 2.002192321 180.63% 0.76 2.08 2.96% 3.003088282 150.59% 0.62 2.57 2.84% 4.004369835 196.20% 0.98 1.62 3.79% 5.005227314 231.98% 0.84 1.90 4.71% v2: Lots of updates. v3: Use slightly narrower columns v4: Add comment Signed-off-by: Andi Kleen <ak@linux.intel.com> Acked-by: Jiri Olsa <jolsa@kernel.org> Link: http://lkml.kernel.org/r/1457049458-28956-6-git-send-email-andi@firstfloor.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2016-03-03 23:57:36 +00:00
--per-socket::
Aggregate counts per processor socket for system-wide mode measurements. This
is a useful mode to detect imbalance between sockets. To enable this mode,
use --per-socket in addition to -a. (system-wide). The output includes the
socket number and the number of online processors on that socket. This is
useful to gauge the amount of aggregation.
--per-core::
Aggregate counts per physical processor for system-wide mode measurements. This
is a useful mode to detect imbalance between physical cores. To enable this mode,
use --per-core in addition to -a. (system-wide). The output includes the
core number and the number of online logical processors on that physical processor.
perf stat: Introduce --per-thread option Currently all the -p option PID arguments tasks values get aggregated and printed as single values. Adding --per-tasks option to print values per task. $ perf stat -e cycles,instructions --per-thread -p 30190,30242 ^C Performance counter stats for process id '30190,30242': cat-30190 0 cycles yes-30242 3,842,525,421 cycles cat-30190 0 instructions yes-30242 10,370,817,010 instructions 1.143155657 seconds time elapsed Also works under interval mode: $ perf stat -e cycles,instructions --per-thread -p 30190,30242 -I 1000 # time comm-pid counts unit events 1.000073435 cat-30190 89,058 cycles 1.000073435 yes-30242 3,360,786,902 cycles (100.00%) 1.000073435 cat-30190 14,066 instructions 1.000073435 yes-30242 9,069,937,462 instructions 2.000204830 cat-30190 0 cycles 2.000204830 yes-30242 3,351,667,626 cycles 2.000204830 cat-30190 0 instructions 2.000204830 yes-30242 9,045,796,885 instructions ^C 2.771286639 cat-30190 0 cycles 2.771286639 yes-30242 2,593,884,166 cycles 2.771286639 cat-30190 0 instructions 2.771286639 yes-30242 7,001,171,191 instructions It works only with -t and -p options, otherwise following error is printed: $ perf stat -e cycles --per-thread -I 1000 ls The --per-thread option is only available when monitoring via -p -t options. -p, --pid <pid> stat events on existing process id -t, --tid <tid> stat events on existing thread id Signed-off-by: Jiri Olsa <jolsa@kernel.org> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: David Ahern <dsahern@gmail.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/r/1435310967-14570-23-git-send-email-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-06-26 09:29:27 +00:00
--per-thread::
Aggregate counts per monitored threads, when monitoring threads (-t option)
or processes (-p option).
perf stat: Add support for --initial-delay option When measuring workloads the startup phase -- doing page faults, dynamic linking, opening files -- is often very different from the rest of the workload. Especially with smaller kernels and using counter multiplexing this can give significant measurement errors. Multiplexing assumes that the workload is mostly the same over longer periods. But at startup there is typically some spike of activity which is relatively short. If many groups are multiplexing the one group seeing the spike, and which is then scaled up over the time to run all groups, may see a significant error. Also in general it's often not useful to measure the startup, because it is so different from the rest. One way around this is to use interval mode and discard the first sample, but this can be awkward because interval mode doesn't support intervals of less than 100ms, and also a useful interval is not necessarily the same as a useful startup delay. This patch adds a new --initial-delay / -D option to skip measuring for the startup phase. The time can be specified in ms Here's a simple example: perf stat -e page-faults bash -c 'for i in $(seq 100000) ; do true ; done' ... 3,721 page-faults ... If we just wait 20 ms the number of page faults is 1/3 less: perf stat -D 20 -e page-faults bash -c 'for i in $(seq 100000) ; do true ; done' ... 2,823 page-faults ... So we filtered out most of the startup noise from bash. Signed-off-by: Andi Kleen <ak@linux.intel.com> Reviewed-by: Jiri Olsa <jolsa@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/r/1375490473-1503-4-git-send-email-andi@firstfloor.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2013-08-03 00:41:11 +00:00
-D msecs::
--delay msecs::
perf stat: Add support for --initial-delay option When measuring workloads the startup phase -- doing page faults, dynamic linking, opening files -- is often very different from the rest of the workload. Especially with smaller kernels and using counter multiplexing this can give significant measurement errors. Multiplexing assumes that the workload is mostly the same over longer periods. But at startup there is typically some spike of activity which is relatively short. If many groups are multiplexing the one group seeing the spike, and which is then scaled up over the time to run all groups, may see a significant error. Also in general it's often not useful to measure the startup, because it is so different from the rest. One way around this is to use interval mode and discard the first sample, but this can be awkward because interval mode doesn't support intervals of less than 100ms, and also a useful interval is not necessarily the same as a useful startup delay. This patch adds a new --initial-delay / -D option to skip measuring for the startup phase. The time can be specified in ms Here's a simple example: perf stat -e page-faults bash -c 'for i in $(seq 100000) ; do true ; done' ... 3,721 page-faults ... If we just wait 20 ms the number of page faults is 1/3 less: perf stat -D 20 -e page-faults bash -c 'for i in $(seq 100000) ; do true ; done' ... 2,823 page-faults ... So we filtered out most of the startup noise from bash. Signed-off-by: Andi Kleen <ak@linux.intel.com> Reviewed-by: Jiri Olsa <jolsa@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/r/1375490473-1503-4-git-send-email-andi@firstfloor.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2013-08-03 00:41:11 +00:00
After starting the program, wait msecs before measuring. This is useful to
filter out the startup phase of the program, which is often very different.
-T::
--transaction::
Print statistics of transactional execution if supported.
perf stat record: Add record command Add 'perf stat record' command support. It creates simple (header only) perf.data file ATM. The record command could be specified anywhere among stat options. All stat command options are valid for stat record command with '-o' option exception. If specified for record command it denotes the perf data file name. Committer note: Set sample_type to PERF_SAMPLE_IDENTIFIER, which should be harmless while avoiding that older tools show confusing messages, for instance, with sample_type = 0, we get: $ perf stat record usleep 1 Performance counter stats for 'usleep 1': 0.630237 task-clock (msec) # 0.528 CPUs utilized 1 context-switches # 0.002 M/sec 0 cpu-migrations # 0.000 K/sec 52 page-faults # 0.083 M/sec 978,312 cycles # 1.552 GHz 671,931 stalled-cycles-frontend # 68.68% frontend cycles idle <not supported> stalled-cycles-backend 646,379 instructions # 0.66 insns per cycle # 1.04 stalled cycles per insn 131,046 branches # 207.931 M/sec 7,073 branch-misses # 5.40% of all branches 0.001193240 seconds time elapsed $ oldperf evlist WARNING: The perf.data file's data size field is 0 which is unexpected. Was the 'perf record' command properly terminated? non matching sample_type $ While with sample_type set to PERF_SAMPLE_IDENTIFIER, after we re-run 'perf stat record usleep' we get: $ oldperf evlist WARNING: The perf.data file's data size field is 0 which is unexpected. Was the 'perf record' command properly terminated? task-clock context-switches cpu-migrations page-faults cycles stalled-cycles-frontend stalled-cycles-backend instructions branches branch-misses $ Which at least shows the names of the events in the perf.data file. Additionally, such files, when passed to 'perf report' will produce: $ oldperf report --stdio WARNING: The perf.data file's data size field is 0 which is unexpected. Was the 'perf record' command properly terminated? Warning: Kernel address maps (/proc/{kallsyms,modules}) were restricted. Check /proc/sys/kernel/kptr_restrict before running 'perf record'. As no suitable kallsyms nor vmlinux was found, kernel samples can't be resolved. Samples in kernel modules can't be resolved as well. Error: The perf.data file has no samples! # To display the perf.data header info, please use --header/--header-only options. # $ Which is confusing and can be solved by just adding the kernel mmap record, which will also remove that warning about the data size field being equal to zero, after generating the mmap record: $ perf stat record usleep 1 Performance counter stats for 'usleep 1': 0.600796 task-clock (msec) # 0.478 CPUs utilized 1 context-switches # 0.002 M/sec 0 cpu-migrations # 0.000 K/sec 54 page-faults # 0.090 M/sec 886,844 cycles # 1.476 GHz 582,169 stalled-cycles-frontend # 65.65% frontend cycles idle <not supported> stalled-cycles-backend 638,344 instructions # 0.72 insns per cycle # 0.91 stalled cycles per insn 130,204 branches # 216.719 M/sec 7,500 branch-misses # 5.76% of all branches 0.001255897 seconds time elapsed $ oldperf evlist task-clock context-switches cpu-migrations page-faults cycles stalled-cycles-frontend stalled-cycles-backend instructions branches branch-misses $ oldperf report --stdio Error: The perf.data file has no samples! # To display the perf.data header info, please use --header/--header-only options. # [acme@zoo linux]$ No warnings, sensible output about what are the events in the perf.data file and also a "file has no samples" message, which indeed it doesn't. Signed-off-by: Jiri Olsa <jolsa@kernel.org> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Tested-by: Kan Liang <kan.liang@intel.com> Cc: David Ahern <dsahern@gmail.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: htp://lkml.kernel.org/r/1446734469-11352-3-git-send-email-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-11-05 14:40:46 +00:00
STAT RECORD
-----------
Stores stat data into perf data file.
-o file::
--output file::
Output file name.
STAT REPORT
-----------
Reads and reports stat data from perf data file.
-i file::
--input file::
Input file name.
--per-socket::
Aggregate counts per processor socket for system-wide mode measurements.
--per-core::
Aggregate counts per physical processor for system-wide mode measurements.
perf stat: Support JSON metrics in perf stat Add generic support for standalone metrics specified in JSON files to perf stat. A metric is a formula that uses multiple events to compute a higher level result (e.g. IPC). Previously metrics were always tied to an event and automatically enabled with that event. But now change it that we can have standalone metrics. They are in the same JSON data structure as events, but don't have an event name. We also allow to organize the metrics in metric groups, which allows a short cut to select several related metrics at once. Add a new -M / --metrics option to perf stat that adds the metrics or metric groups specified. Add the core code to manage and parse the metric groups. They are collected from the JSON data structures into a separate rblist. When computing shadow values look for metrics in that list. Then they are computed using the existing saved values infrastructure in stat-shadow.c The actual JSON metrics are in a separate pull request. % perf stat -M Summary --metric-only -a sleep 1 Performance counter stats for 'system wide': Instructions CLKS CPU_Utilization GFLOPs SMT_2T_Utilization Kernel_Utilization 317614222.0 1392930775.0 0.0 0.0 0.2 0.1 1.001497549 seconds time elapsed % perf stat -M GFLOPs flops Performance counter stats for 'flops': 3,999,541,471 fp_comp_ops_exe.sse_scalar_single # 1.2 GFLOPs (66.65%) 14 fp_comp_ops_exe.sse_scalar_double (66.65%) 0 fp_comp_ops_exe.sse_packed_double (66.67%) 0 fp_comp_ops_exe.sse_packed_single (66.70%) 0 simd_fp_256.packed_double (66.70%) 0 simd_fp_256.packed_single (66.67%) 0 duration_time 3.238372845 seconds time elapsed v2: Add missing header file v3: Move find_map to pmu.c Signed-off-by: Andi Kleen <ak@linux.intel.com> Acked-by: Jiri Olsa <jolsa@kernel.org> Link: http://lkml.kernel.org/r/20170831194036.30146-7-andi@firstfloor.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2017-08-31 19:40:31 +00:00
-M::
--metrics::
Print metrics or metricgroups specified in a comma separated list.
For a group all metrics from the group are added.
The events from the metrics are automatically measured.
See perf list output for the possble metrics and metricgroups.
-A::
--no-aggr::
Do not aggregate counts across all monitored CPUs.
perf stat: Basic support for TopDown in perf stat Add basic plumbing for TopDown in perf stat TopDown is intended to replace the frontend cycles idle/ backend cycles idle metrics in standard perf stat output. These metrics are not reliable in many workloads, due to out of order effects. This implements a new --topdown mode in perf stat (similar to --transaction) that measures the pipe line bottlenecks using standardized formulas. The measurement can be all done with 5 counters (one fixed counter) The result are four metrics: FrontendBound, BackendBound, BadSpeculation, Retiring that describe the CPU pipeline behavior on a high level. The full top down methology has many hierarchical metrics. This implementation only supports level 1 which can be collected without multiplexing. A full implementation of top down on top of perf is available in pmu-tools toplev. (http://github.com/andikleen/pmu-tools) The current version works on Intel Core CPUs starting with Sandy Bridge, and Atom CPUs starting with Silvermont. In principle the generic metrics should be also implementable on other out of order CPUs. TopDown level 1 uses a set of abstracted metrics which are generic to out of order CPU cores (although some CPUs may not implement all of them): topdown-total-slots Available slots in the pipeline topdown-slots-issued Slots issued into the pipeline topdown-slots-retired Slots successfully retired topdown-fetch-bubbles Pipeline gaps in the frontend topdown-recovery-bubbles Pipeline gaps during recovery from misspeculation These metrics then allow to compute four useful metrics: FrontendBound, BackendBound, Retiring, BadSpeculation. Add a new --topdown options to enable events. When --topdown is specified set up events for all topdown events supported by the kernel. Add topdown-* as a special case to the event parser, as is needed for all events containing -. The actual code to compute the metrics is in follow-on patches. v2: Use standard sysctl read function. v3: Move x86 specific code to arch/ v4: Enable --metric-only implicitly for topdown. v5: Add --single-thread option to not force per core mode v6: Fix output order of topdown metrics v7: Allow combining with -d v8: Remove --single-thread again v9: Rename functions, adding arch_ and topdown_. v10: Expand man page and describe TopDown better Paste intro into commit description. Print error when malloc fails. Signed-off-by: Andi Kleen <ak@linux.intel.com> Acked-by: Jiri Olsa <jolsa@kernel.org> Link: http://lkml.kernel.org/r/1464119559-17203-1-git-send-email-andi@firstfloor.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2016-05-30 15:49:42 +00:00
--topdown::
Print top down level 1 metrics if supported by the CPU. This allows to
determine bottle necks in the CPU pipeline for CPU bound workloads,
by breaking the cycles consumed down into frontend bound, backend bound,
bad speculation and retiring.
Frontend bound means that the CPU cannot fetch and decode instructions fast
enough. Backend bound means that computation or memory access is the bottle
neck. Bad Speculation means that the CPU wasted cycles due to branch
mispredictions and similar issues. Retiring means that the CPU computed without
an apparently bottleneck. The bottleneck is only the real bottleneck
if the workload is actually bound by the CPU and not by something else.
For best results it is usually a good idea to use it with interval
mode like -I 1000, as the bottleneck of workloads can change often.
The top down metrics are collected per core instead of per
CPU thread. Per core mode is automatically enabled
and -a (global monitoring) is needed, requiring root rights or
perf.perf_event_paranoid=-1.
Topdown uses the full Performance Monitoring Unit, and needs
disabling of the NMI watchdog (as root):
echo 0 > /proc/sys/kernel/nmi_watchdog
for best results. Otherwise the bottlenecks may be inconsistent
on workload with changing phases.
This enables --metric-only, unless overridden with --no-metric-only.
perf stat: Basic support for TopDown in perf stat Add basic plumbing for TopDown in perf stat TopDown is intended to replace the frontend cycles idle/ backend cycles idle metrics in standard perf stat output. These metrics are not reliable in many workloads, due to out of order effects. This implements a new --topdown mode in perf stat (similar to --transaction) that measures the pipe line bottlenecks using standardized formulas. The measurement can be all done with 5 counters (one fixed counter) The result are four metrics: FrontendBound, BackendBound, BadSpeculation, Retiring that describe the CPU pipeline behavior on a high level. The full top down methology has many hierarchical metrics. This implementation only supports level 1 which can be collected without multiplexing. A full implementation of top down on top of perf is available in pmu-tools toplev. (http://github.com/andikleen/pmu-tools) The current version works on Intel Core CPUs starting with Sandy Bridge, and Atom CPUs starting with Silvermont. In principle the generic metrics should be also implementable on other out of order CPUs. TopDown level 1 uses a set of abstracted metrics which are generic to out of order CPU cores (although some CPUs may not implement all of them): topdown-total-slots Available slots in the pipeline topdown-slots-issued Slots issued into the pipeline topdown-slots-retired Slots successfully retired topdown-fetch-bubbles Pipeline gaps in the frontend topdown-recovery-bubbles Pipeline gaps during recovery from misspeculation These metrics then allow to compute four useful metrics: FrontendBound, BackendBound, Retiring, BadSpeculation. Add a new --topdown options to enable events. When --topdown is specified set up events for all topdown events supported by the kernel. Add topdown-* as a special case to the event parser, as is needed for all events containing -. The actual code to compute the metrics is in follow-on patches. v2: Use standard sysctl read function. v3: Move x86 specific code to arch/ v4: Enable --metric-only implicitly for topdown. v5: Add --single-thread option to not force per core mode v6: Fix output order of topdown metrics v7: Allow combining with -d v8: Remove --single-thread again v9: Rename functions, adding arch_ and topdown_. v10: Expand man page and describe TopDown better Paste intro into commit description. Print error when malloc fails. Signed-off-by: Andi Kleen <ak@linux.intel.com> Acked-by: Jiri Olsa <jolsa@kernel.org> Link: http://lkml.kernel.org/r/1464119559-17203-1-git-send-email-andi@firstfloor.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2016-05-30 15:49:42 +00:00
To interpret the results it is usually needed to know on which
CPUs the workload runs on. If needed the CPUs can be forced using
taskset.
perf stat record: Add record command Add 'perf stat record' command support. It creates simple (header only) perf.data file ATM. The record command could be specified anywhere among stat options. All stat command options are valid for stat record command with '-o' option exception. If specified for record command it denotes the perf data file name. Committer note: Set sample_type to PERF_SAMPLE_IDENTIFIER, which should be harmless while avoiding that older tools show confusing messages, for instance, with sample_type = 0, we get: $ perf stat record usleep 1 Performance counter stats for 'usleep 1': 0.630237 task-clock (msec) # 0.528 CPUs utilized 1 context-switches # 0.002 M/sec 0 cpu-migrations # 0.000 K/sec 52 page-faults # 0.083 M/sec 978,312 cycles # 1.552 GHz 671,931 stalled-cycles-frontend # 68.68% frontend cycles idle <not supported> stalled-cycles-backend 646,379 instructions # 0.66 insns per cycle # 1.04 stalled cycles per insn 131,046 branches # 207.931 M/sec 7,073 branch-misses # 5.40% of all branches 0.001193240 seconds time elapsed $ oldperf evlist WARNING: The perf.data file's data size field is 0 which is unexpected. Was the 'perf record' command properly terminated? non matching sample_type $ While with sample_type set to PERF_SAMPLE_IDENTIFIER, after we re-run 'perf stat record usleep' we get: $ oldperf evlist WARNING: The perf.data file's data size field is 0 which is unexpected. Was the 'perf record' command properly terminated? task-clock context-switches cpu-migrations page-faults cycles stalled-cycles-frontend stalled-cycles-backend instructions branches branch-misses $ Which at least shows the names of the events in the perf.data file. Additionally, such files, when passed to 'perf report' will produce: $ oldperf report --stdio WARNING: The perf.data file's data size field is 0 which is unexpected. Was the 'perf record' command properly terminated? Warning: Kernel address maps (/proc/{kallsyms,modules}) were restricted. Check /proc/sys/kernel/kptr_restrict before running 'perf record'. As no suitable kallsyms nor vmlinux was found, kernel samples can't be resolved. Samples in kernel modules can't be resolved as well. Error: The perf.data file has no samples! # To display the perf.data header info, please use --header/--header-only options. # $ Which is confusing and can be solved by just adding the kernel mmap record, which will also remove that warning about the data size field being equal to zero, after generating the mmap record: $ perf stat record usleep 1 Performance counter stats for 'usleep 1': 0.600796 task-clock (msec) # 0.478 CPUs utilized 1 context-switches # 0.002 M/sec 0 cpu-migrations # 0.000 K/sec 54 page-faults # 0.090 M/sec 886,844 cycles # 1.476 GHz 582,169 stalled-cycles-frontend # 65.65% frontend cycles idle <not supported> stalled-cycles-backend 638,344 instructions # 0.72 insns per cycle # 0.91 stalled cycles per insn 130,204 branches # 216.719 M/sec 7,500 branch-misses # 5.76% of all branches 0.001255897 seconds time elapsed $ oldperf evlist task-clock context-switches cpu-migrations page-faults cycles stalled-cycles-frontend stalled-cycles-backend instructions branches branch-misses $ oldperf report --stdio Error: The perf.data file has no samples! # To display the perf.data header info, please use --header/--header-only options. # [acme@zoo linux]$ No warnings, sensible output about what are the events in the perf.data file and also a "file has no samples" message, which indeed it doesn't. Signed-off-by: Jiri Olsa <jolsa@kernel.org> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Tested-by: Kan Liang <kan.liang@intel.com> Cc: David Ahern <dsahern@gmail.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: htp://lkml.kernel.org/r/1446734469-11352-3-git-send-email-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-11-05 14:40:46 +00:00
perf stat: Collapse identically named events The uncore PMU has a lot of duplicated PMUs for different subsystems. When expanding an uncore alias we usually end up with a large number of identically named aliases, which makes perf stat output difficult to read. Automatically sum them up in perf stat, unless --no-merge is specified. This can be default because only the uncores generally have duplicated aliases. Other PMUs have unique names. Before: % perf stat --no-merge -a -e unc_c_llc_lookup.any sleep 1 Performance counter stats for 'system wide': 694,976 Bytes unc_c_llc_lookup.any 706,304 Bytes unc_c_llc_lookup.any 956,608 Bytes unc_c_llc_lookup.any 782,720 Bytes unc_c_llc_lookup.any 605,696 Bytes unc_c_llc_lookup.any 442,816 Bytes unc_c_llc_lookup.any 659,328 Bytes unc_c_llc_lookup.any 509,312 Bytes unc_c_llc_lookup.any 263,936 Bytes unc_c_llc_lookup.any 592,448 Bytes unc_c_llc_lookup.any 672,448 Bytes unc_c_llc_lookup.any 608,640 Bytes unc_c_llc_lookup.any 641,024 Bytes unc_c_llc_lookup.any 856,896 Bytes unc_c_llc_lookup.any 808,832 Bytes unc_c_llc_lookup.any 684,864 Bytes unc_c_llc_lookup.any 710,464 Bytes unc_c_llc_lookup.any 538,304 Bytes unc_c_llc_lookup.any 1.002577660 seconds time elapsed After: % perf stat -a -e unc_c_llc_lookup.any sleep 1 Performance counter stats for 'system wide': 2,685,120 Bytes unc_c_llc_lookup.any 1.002648032 seconds time elapsed v2: Split collect_aliases. Rename alias flag. v3: Make sure unsupported/not counted is always printed. v4: Factor out callback change into separate patch. v5: Move check for bad results here Move merged check into collect_data Signed-off-by: Andi Kleen <ak@linux.intel.com> Acked-by: Jiri Olsa <jolsa@kernel.org> Link: http://lkml.kernel.org/r/20170320201711.14142-3-andi@firstfloor.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2017-03-20 20:17:00 +00:00
--no-merge::
Do not merge results from same PMUs.
perf pmu: Auto-merge PMU events created by prefix or glob match Auto-merge for these events was disabled when auto-merging of non-alias events was disabled in commit 63ce844 (perf stat: Only auto-merge events that are PMU aliases). Non-merging of legacy events is preserved: $ perf stat -ag -e cache-misses,cache-misses sleep 1 Performance counter stats for 'system wide': 86,323 cache-misses 86,323 cache-misses 1.002623307 seconds time elapsed But prefix or glob matching auto-merges the events created: $ perf stat -a -e l3cache/read-miss/ sleep 1 Performance counter stats for 'system wide': 328 l3cache/read-miss/ 1.002627008 seconds time elapsed $ perf stat -a -e l3cache_0_[01]/read-miss/ sleep 1 Performance counter stats for 'system wide': 172 l3cache/read-miss/ 1.002627008 seconds time elapsed As with events created with aliases, auto-merging can be suppressed with the --no-merge option: $ perf stat -a -e l3cache/read-miss/ --no-merge sleep 1 Performance counter stats for 'system wide': 67 l3cache/read-miss/ 67 l3cache/read-miss/ 63 l3cache/read-miss/ 60 l3cache/read-miss/ 1.002622192 seconds time elapsed Signed-off-by: Agustin Vega-Frias <agustinv@codeaurora.org> Acked-by: Andi Kleen <ak@linux.intel.com> Acked-by: Jiri Olsa <jolsa@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Timur Tabi <timur@codeaurora.org> Cc: linux-arm-kernel@lists.infradead.org Change-Id: I0a47eed54c05e1982ca964d743b37f50f60c508c Link: http://lkml.kernel.org/r/1520345084-42646-4-git-send-email-agustinv@codeaurora.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2018-03-06 14:04:44 +00:00
When multiple events are created from a single event specification,
stat will, by default, aggregate the event counts and show the result
in a single row. This option disables that behavior and shows
the individual events and counts.
Multiple events are created from a single event specification when:
1. Prefix or glob matching is used for the PMU name.
2. Aliases, which are listed immediately after the Kernel PMU events
by perf list, are used.
--smi-cost::
Measure SMI cost if msr/aperf/ and msr/smi/ events are supported.
During the measurement, the /sys/device/cpu/freeze_on_smi will be set to
freeze core counters on SMI.
The aperf counter will not be effected by the setting.
The cost of SMI can be measured by (aperf - unhalted core cycles).
In practice, the percentages of SMI cycles is very useful for performance
oriented analysis. --metric_only will be applied by default.
The output is SMI cycles%, equals to (aperf - unhalted core cycles) / aperf
Users who wants to get the actual value can apply --no-metric-only.
EXAMPLES
--------
perf stat: Display user and system time Adding the support to read rusage data once the workload is finished and display the system/user time values: $ perf stat --null perf bench sched pipe ... Performance counter stats for 'perf bench sched pipe': 5.342599256 seconds time elapsed 2.544434000 seconds user 4.549691000 seconds sys It works only in non -r mode and only for workload target. So as of now, for workload targets, we display 3 types of timings. The time we meassure in perf stat from enable to disable+period: 5.342599256 seconds time elapsed The time spent in user and system lands, displayed only for workload session/target: 2.544434000 seconds user 4.549691000 seconds sys Those times are the very same displayed by 'time' tool. They are returned by wait4 call via the getrusage struct interface. Committer notes: Had to rename some variables to avoid this on older systems such as centos:6: builtin-stat.c: In function 'print_footer': builtin-stat.c:1831: warning: declaration of 'stime' shadows a global declaration /usr/include/time.h:297: warning: shadowed declaration is here Committer testing: # perf stat --null time perf bench sched pipe # Running 'sched/pipe' benchmark: # Executed 1000000 pipe operations between two processes Total time: 5.526 [sec] 5.526534 usecs/op 180945 ops/sec 1.00user 6.25system 0:05.52elapsed 131%CPU (0avgtext+0avgdata 8056maxresident)k 0inputs+0outputs (0major+606minor)pagefaults 0swaps Performance counter stats for 'time perf bench sched pipe': 5.530978744 seconds time elapsed 1.004037000 seconds user 6.259937000 seconds sys # Suggested-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Jiri Olsa <jolsa@kernel.org> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: David Ahern <dsahern@gmail.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20180605121313.31337-1-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2018-06-05 12:13:13 +00:00
$ perf stat -- make
perf stat: Display user and system time Adding the support to read rusage data once the workload is finished and display the system/user time values: $ perf stat --null perf bench sched pipe ... Performance counter stats for 'perf bench sched pipe': 5.342599256 seconds time elapsed 2.544434000 seconds user 4.549691000 seconds sys It works only in non -r mode and only for workload target. So as of now, for workload targets, we display 3 types of timings. The time we meassure in perf stat from enable to disable+period: 5.342599256 seconds time elapsed The time spent in user and system lands, displayed only for workload session/target: 2.544434000 seconds user 4.549691000 seconds sys Those times are the very same displayed by 'time' tool. They are returned by wait4 call via the getrusage struct interface. Committer notes: Had to rename some variables to avoid this on older systems such as centos:6: builtin-stat.c: In function 'print_footer': builtin-stat.c:1831: warning: declaration of 'stime' shadows a global declaration /usr/include/time.h:297: warning: shadowed declaration is here Committer testing: # perf stat --null time perf bench sched pipe # Running 'sched/pipe' benchmark: # Executed 1000000 pipe operations between two processes Total time: 5.526 [sec] 5.526534 usecs/op 180945 ops/sec 1.00user 6.25system 0:05.52elapsed 131%CPU (0avgtext+0avgdata 8056maxresident)k 0inputs+0outputs (0major+606minor)pagefaults 0swaps Performance counter stats for 'time perf bench sched pipe': 5.530978744 seconds time elapsed 1.004037000 seconds user 6.259937000 seconds sys # Suggested-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Jiri Olsa <jolsa@kernel.org> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: David Ahern <dsahern@gmail.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20180605121313.31337-1-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2018-06-05 12:13:13 +00:00
Performance counter stats for 'make':
perf stat: Display user and system time Adding the support to read rusage data once the workload is finished and display the system/user time values: $ perf stat --null perf bench sched pipe ... Performance counter stats for 'perf bench sched pipe': 5.342599256 seconds time elapsed 2.544434000 seconds user 4.549691000 seconds sys It works only in non -r mode and only for workload target. So as of now, for workload targets, we display 3 types of timings. The time we meassure in perf stat from enable to disable+period: 5.342599256 seconds time elapsed The time spent in user and system lands, displayed only for workload session/target: 2.544434000 seconds user 4.549691000 seconds sys Those times are the very same displayed by 'time' tool. They are returned by wait4 call via the getrusage struct interface. Committer notes: Had to rename some variables to avoid this on older systems such as centos:6: builtin-stat.c: In function 'print_footer': builtin-stat.c:1831: warning: declaration of 'stime' shadows a global declaration /usr/include/time.h:297: warning: shadowed declaration is here Committer testing: # perf stat --null time perf bench sched pipe # Running 'sched/pipe' benchmark: # Executed 1000000 pipe operations between two processes Total time: 5.526 [sec] 5.526534 usecs/op 180945 ops/sec 1.00user 6.25system 0:05.52elapsed 131%CPU (0avgtext+0avgdata 8056maxresident)k 0inputs+0outputs (0major+606minor)pagefaults 0swaps Performance counter stats for 'time perf bench sched pipe': 5.530978744 seconds time elapsed 1.004037000 seconds user 6.259937000 seconds sys # Suggested-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Jiri Olsa <jolsa@kernel.org> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: David Ahern <dsahern@gmail.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20180605121313.31337-1-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2018-06-05 12:13:13 +00:00
83723.452481 task-clock:u (msec) # 1.004 CPUs utilized
0 context-switches:u # 0.000 K/sec
0 cpu-migrations:u # 0.000 K/sec
3,228,188 page-faults:u # 0.039 M/sec
229,570,665,834 cycles:u # 2.742 GHz
313,163,853,778 instructions:u # 1.36 insn per cycle
69,704,684,856 branches:u # 832.559 M/sec
2,078,861,393 branch-misses:u # 2.98% of all branches
perf stat: Display user and system time Adding the support to read rusage data once the workload is finished and display the system/user time values: $ perf stat --null perf bench sched pipe ... Performance counter stats for 'perf bench sched pipe': 5.342599256 seconds time elapsed 2.544434000 seconds user 4.549691000 seconds sys It works only in non -r mode and only for workload target. So as of now, for workload targets, we display 3 types of timings. The time we meassure in perf stat from enable to disable+period: 5.342599256 seconds time elapsed The time spent in user and system lands, displayed only for workload session/target: 2.544434000 seconds user 4.549691000 seconds sys Those times are the very same displayed by 'time' tool. They are returned by wait4 call via the getrusage struct interface. Committer notes: Had to rename some variables to avoid this on older systems such as centos:6: builtin-stat.c: In function 'print_footer': builtin-stat.c:1831: warning: declaration of 'stime' shadows a global declaration /usr/include/time.h:297: warning: shadowed declaration is here Committer testing: # perf stat --null time perf bench sched pipe # Running 'sched/pipe' benchmark: # Executed 1000000 pipe operations between two processes Total time: 5.526 [sec] 5.526534 usecs/op 180945 ops/sec 1.00user 6.25system 0:05.52elapsed 131%CPU (0avgtext+0avgdata 8056maxresident)k 0inputs+0outputs (0major+606minor)pagefaults 0swaps Performance counter stats for 'time perf bench sched pipe': 5.530978744 seconds time elapsed 1.004037000 seconds user 6.259937000 seconds sys # Suggested-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Jiri Olsa <jolsa@kernel.org> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: David Ahern <dsahern@gmail.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20180605121313.31337-1-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2018-06-05 12:13:13 +00:00
83.409183620 seconds time elapsed
74.684747000 seconds user
8.739217000 seconds sys
TIMINGS
-------
As displayed in the example above we can display 3 types of timings.
We always display the time the counters were enabled/alive:
83.409183620 seconds time elapsed
For workload sessions we also display time the workloads spent in
user/system lands:
74.684747000 seconds user
8.739217000 seconds sys
Those times are the very same as displayed by the 'time' tool.
CSV FORMAT
----------
With -x, perf stat is able to output a not-quite-CSV format output
Commas in the output are not put into "". To make it easy to parse
it is recommended to use a different character like -x \;
The fields are in this order:
- optional usec time stamp in fractions of second (with -I xxx)
- optional CPU, core, or socket identifier
- optional number of logical CPUs aggregated
- counter value
- unit of the counter value or empty
- event name
- run time of counter
- percentage of measurement time the counter was running
- optional variance if multiple values are collected with -r
- optional metric value
- optional unit of metric
Additional metrics may be printed with all earlier fields being empty.
SEE ALSO
--------
linkperf:perf-top[1], linkperf:perf-list[1]