mirror of
https://github.com/torvalds/linux.git
synced 2024-11-29 23:51:37 +00:00
c8d6828a65
Previously we were dropping the useful longer descriptions that some
events have in the event list completely. This patch makes them appear with
perf list.
Old perf list:
baclears:
baclears.all
[Counts the number of baclears]
vs new:
perf list -v:
...
baclears:
baclears.all
[The BACLEARS event counts the number of times the front end is
resteered, mainly when the Branch Prediction Unit cannot provide
a correct prediction and this is corrected by the Branch Address
Calculator at the front end. The BACLEARS.ANY event counts the
number of baclears for any type of branch]
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Cc: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: linuxppc-dev@lists.ozlabs.org
Link: http://lkml.kernel.org/r/1473978296-20712-13-git-send-email-sukadev@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
263 lines
8.8 KiB
Plaintext
263 lines
8.8 KiB
Plaintext
perf-list(1)
|
||
============
|
||
|
||
NAME
|
||
----
|
||
perf-list - List all symbolic event types
|
||
|
||
SYNOPSIS
|
||
--------
|
||
[verse]
|
||
'perf list' [--no-desc] [--long-desc] [hw|sw|cache|tracepoint|pmu|event_glob]
|
||
|
||
DESCRIPTION
|
||
-----------
|
||
This command displays the symbolic event types which can be selected in the
|
||
various perf commands with the -e option.
|
||
|
||
OPTIONS
|
||
-------
|
||
--no-desc::
|
||
Don't print descriptions.
|
||
|
||
-v::
|
||
--long-desc::
|
||
Print longer event descriptions.
|
||
|
||
|
||
[[EVENT_MODIFIERS]]
|
||
EVENT MODIFIERS
|
||
---------------
|
||
|
||
Events can optionally have a modifier by appending a colon and one or
|
||
more modifiers. Modifiers allow the user to restrict the events to be
|
||
counted. The following modifiers exist:
|
||
|
||
u - user-space counting
|
||
k - kernel counting
|
||
h - hypervisor counting
|
||
I - non idle counting
|
||
G - guest counting (in KVM guests)
|
||
H - host counting (not in KVM guests)
|
||
p - precise level
|
||
P - use maximum detected precise level
|
||
S - read sample value (PERF_SAMPLE_READ)
|
||
D - pin the event to the PMU
|
||
|
||
The 'p' modifier can be used for specifying how precise the instruction
|
||
address should be. The 'p' modifier can be specified multiple times:
|
||
|
||
0 - SAMPLE_IP can have arbitrary skid
|
||
1 - SAMPLE_IP must have constant skid
|
||
2 - SAMPLE_IP requested to have 0 skid
|
||
3 - SAMPLE_IP must have 0 skid, or uses randomization to avoid
|
||
sample shadowing effects.
|
||
|
||
For Intel systems precise event sampling is implemented with PEBS
|
||
which supports up to precise-level 2, and precise level 3 for
|
||
some special cases
|
||
|
||
On AMD systems it is implemented using IBS (up to precise-level 2).
|
||
The precise modifier works with event types 0x76 (cpu-cycles, CPU
|
||
clocks not halted) and 0xC1 (micro-ops retired). Both events map to
|
||
IBS execution sampling (IBS op) with the IBS Op Counter Control bit
|
||
(IbsOpCntCtl) set respectively (see AMD64 Architecture Programmer’s
|
||
Manual Volume 2: System Programming, 13.3 Instruction-Based
|
||
Sampling). Examples to use IBS:
|
||
|
||
perf record -a -e cpu-cycles:p ... # use ibs op counting cycles
|
||
perf record -a -e r076:p ... # same as -e cpu-cycles:p
|
||
perf record -a -e r0C1:p ... # use ibs op counting micro-ops
|
||
|
||
RAW HARDWARE EVENT DESCRIPTOR
|
||
-----------------------------
|
||
Even when an event is not available in a symbolic form within perf right now,
|
||
it can be encoded in a per processor specific way.
|
||
|
||
For instance For x86 CPUs NNN represents the raw register encoding with the
|
||
layout of IA32_PERFEVTSELx MSRs (see [Intel® 64 and IA-32 Architectures Software Developer's Manual Volume 3B: System Programming Guide] Figure 30-1 Layout
|
||
of IA32_PERFEVTSELx MSRs) or AMD's PerfEvtSeln (see [AMD64 Architecture Programmer’s Manual Volume 2: System Programming], Page 344,
|
||
Figure 13-7 Performance Event-Select Register (PerfEvtSeln)).
|
||
|
||
Note: Only the following bit fields can be set in x86 counter
|
||
registers: event, umask, edge, inv, cmask. Esp. guest/host only and
|
||
OS/user mode flags must be setup using <<EVENT_MODIFIERS, EVENT
|
||
MODIFIERS>>.
|
||
|
||
Example:
|
||
|
||
If the Intel docs for a QM720 Core i7 describe an event as:
|
||
|
||
Event Umask Event Mask
|
||
Num. Value Mnemonic Description Comment
|
||
|
||
A8H 01H LSD.UOPS Counts the number of micro-ops Use cmask=1 and
|
||
delivered by loop stream detector invert to count
|
||
cycles
|
||
|
||
raw encoding of 0x1A8 can be used:
|
||
|
||
perf stat -e r1a8 -a sleep 1
|
||
perf record -e r1a8 ...
|
||
|
||
You should refer to the processor specific documentation for getting these
|
||
details. Some of them are referenced in the SEE ALSO section below.
|
||
|
||
ARBITRARY PMUS
|
||
--------------
|
||
|
||
perf also supports an extended syntax for specifying raw parameters
|
||
to PMUs. Using this typically requires looking up the specific event
|
||
in the CPU vendor specific documentation.
|
||
|
||
The available PMUs and their raw parameters can be listed with
|
||
|
||
ls /sys/devices/*/format
|
||
|
||
For example the raw event "LSD.UOPS" core pmu event above could
|
||
be specified as
|
||
|
||
perf stat -e cpu/event=0xa8,umask=0x1,name=LSD.UOPS_CYCLES,cmask=1/ ...
|
||
|
||
PER SOCKET PMUS
|
||
---------------
|
||
|
||
Some PMUs are not associated with a core, but with a whole CPU socket.
|
||
Events on these PMUs generally cannot be sampled, but only counted globally
|
||
with perf stat -a. They can be bound to one logical CPU, but will measure
|
||
all the CPUs in the same socket.
|
||
|
||
This example measures memory bandwidth every second
|
||
on the first memory controller on socket 0 of a Intel Xeon system
|
||
|
||
perf stat -C 0 -a uncore_imc_0/cas_count_read/,uncore_imc_0/cas_count_write/ -I 1000 ...
|
||
|
||
Each memory controller has its own PMU. Measuring the complete system
|
||
bandwidth would require specifying all imc PMUs (see perf list output),
|
||
and adding the values together.
|
||
|
||
This example measures the combined core power every second
|
||
|
||
perf stat -I 1000 -e power/energy-cores/ -a
|
||
|
||
ACCESS RESTRICTIONS
|
||
-------------------
|
||
|
||
For non root users generally only context switched PMU events are available.
|
||
This is normally only the events in the cpu PMU, the predefined events
|
||
like cycles and instructions and some software events.
|
||
|
||
Other PMUs and global measurements are normally root only.
|
||
Some event qualifiers, such as "any", are also root only.
|
||
|
||
This can be overriden by setting the kernel.perf_event_paranoid
|
||
sysctl to -1, which allows non root to use these events.
|
||
|
||
For accessing trace point events perf needs to have read access to
|
||
/sys/kernel/debug/tracing, even when perf_event_paranoid is in a relaxed
|
||
setting.
|
||
|
||
TRACING
|
||
-------
|
||
|
||
Some PMUs control advanced hardware tracing capabilities, such as Intel PT,
|
||
that allows low overhead execution tracing. These are described in a separate
|
||
intel-pt.txt document.
|
||
|
||
PARAMETERIZED EVENTS
|
||
--------------------
|
||
|
||
Some pmu events listed by 'perf-list' will be displayed with '?' in them. For
|
||
example:
|
||
|
||
hv_gpci/dtbp_ptitc,phys_processor_idx=?/
|
||
|
||
This means that when provided as an event, a value for '?' must
|
||
also be supplied. For example:
|
||
|
||
perf stat -C 0 -e 'hv_gpci/dtbp_ptitc,phys_processor_idx=0x2/' ...
|
||
|
||
EVENT GROUPS
|
||
------------
|
||
|
||
Perf supports time based multiplexing of events, when the number of events
|
||
active exceeds the number of hardware performance counters. Multiplexing
|
||
can cause measurement errors when the workload changes its execution
|
||
profile.
|
||
|
||
When metrics are computed using formulas from event counts, it is useful to
|
||
ensure some events are always measured together as a group to minimize multiplexing
|
||
errors. Event groups can be specified using { }.
|
||
|
||
perf stat -e '{instructions,cycles}' ...
|
||
|
||
The number of available performance counters depend on the CPU. A group
|
||
cannot contain more events than available counters.
|
||
For example Intel Core CPUs typically have four generic performance counters
|
||
for the core, plus three fixed counters for instructions, cycles and
|
||
ref-cycles. Some special events have restrictions on which counter they
|
||
can schedule, and may not support multiple instances in a single group.
|
||
When too many events are specified in the group none of them will not
|
||
be measured.
|
||
|
||
Globally pinned events can limit the number of counters available for
|
||
other groups. On x86 systems, the NMI watchdog pins a counter by default.
|
||
The nmi watchdog can be disabled as root with
|
||
|
||
echo 0 > /proc/sys/kernel/nmi_watchdog
|
||
|
||
Events from multiple different PMUs cannot be mixed in a group, with
|
||
some exceptions for software events.
|
||
|
||
LEADER SAMPLING
|
||
---------------
|
||
|
||
perf also supports group leader sampling using the :S specifier.
|
||
|
||
perf record -e '{cycles,instructions}:S' ...
|
||
perf report --group
|
||
|
||
Normally all events in a event group sample, but with :S only
|
||
the first event (the leader) samples, and it only reads the values of the
|
||
other events in the group.
|
||
|
||
OPTIONS
|
||
-------
|
||
|
||
Without options all known events will be listed.
|
||
|
||
To limit the list use:
|
||
|
||
. 'hw' or 'hardware' to list hardware events such as cache-misses, etc.
|
||
|
||
. 'sw' or 'software' to list software events such as context switches, etc.
|
||
|
||
. 'cache' or 'hwcache' to list hardware cache events such as L1-dcache-loads, etc.
|
||
|
||
. 'tracepoint' to list all tracepoint events, alternatively use
|
||
'subsys_glob:event_glob' to filter by tracepoint subsystems such as sched,
|
||
block, etc.
|
||
|
||
. 'pmu' to print the kernel supplied PMU events.
|
||
|
||
. If none of the above is matched, it will apply the supplied glob to all
|
||
events, printing the ones that match.
|
||
|
||
. As a last resort, it will do a substring search in all event names.
|
||
|
||
One or more types can be used at the same time, listing the events for the
|
||
types specified.
|
||
|
||
Support raw format:
|
||
|
||
. '--raw-dump', shows the raw-dump of all the events.
|
||
. '--raw-dump [hw|sw|cache|tracepoint|pmu|event_glob]', shows the raw-dump of
|
||
a certain kind of events.
|
||
|
||
SEE ALSO
|
||
--------
|
||
linkperf:perf-stat[1], linkperf:perf-top[1],
|
||
linkperf:perf-record[1],
|
||
http://www.intel.com/sdm/[Intel® 64 and IA-32 Architectures Software Developer's Manual Volume 3B: System Programming Guide],
|
||
http://support.amd.com/us/Processor_TechDocs/24593_APM_v2.pdf[AMD64 Architecture Programmer’s Manual Volume 2: System Programming]
|