linux/tools/perf
Ravi Bangoria 9ab95b0b15 perf record ibs: Warn about sampling period skew
Samples without an L3 miss are discarded and counter is reset with
random value (between 1-15 for fetch PMU and 1-127 for op PMU) when IBS
L3 miss filtering is enabled. This causes a sampling period skew but
there is no way to reconstruct aggregated sampling period. So print a
warning at perf record if user sets l3missonly=1.

Ex:

  # perf record -c 10000 -C 0 -e ibs_op/l3missonly=1/
  WARNING: Hw internally resets sampling period when L3 Miss Filtering is enabled
  and tagged operation does not cause L3 Miss. This causes sampling period skew.

Signed-off-by: Ravi Bangoria <ravi.bangoria@amd.com>
Acked-by: Ian Rogers <irogers@google.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Ananth Narayan <ananth.narayan@amd.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: James Clark <james.clark@arm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Kim Phillips <kim.phillips@amd.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Robert Richter <rrichter@amd.com>
Cc: Sandipan Das <sandipan.das@amd.com>
Cc: Santosh Shukla <santosh.shukla@amd.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: like.xu.linux@gmail.com
Cc: x86@kernel.org
Link: http://lore.kernel.org/lkml/20220604044519.594-2-ravi.bangoria@amd.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2022-06-24 13:18:22 -03:00
..
arch perf record ibs: Warn about sampling period skew 2022-06-24 13:18:22 -03:00
bench Merge remote-tracking branch 'torvalds/master' into perf/core 2022-05-23 09:32:49 -03:00
dlfilters perf dlfilter: Drop unused variable 2021-12-16 12:18:11 -03:00
Documentation perf record: Add finished init event 2022-06-23 11:54:22 -03:00
examples/bpf
include perf build: Move perf_dlfilters.h in the source tree 2021-08-11 09:35:24 -03:00
jvmti
pmu-events perf vendor events intel: Update metrics for Alderlake 2022-06-03 21:45:32 +02:00
python perf python: Convert tracepoint.py example to python3 2022-04-01 16:19:35 -03:00
scripts perf scripts python: Support Arm CoreSight trace data disassembly 2022-05-27 13:22:14 -03:00
tests perf expr: Allow exponents on floating point values 2022-06-19 10:41:43 -03:00
trace perf beauty: Update copy of linux/socket.h with the kernel sources 2022-06-19 10:41:43 -03:00
ui perf annotate: Avoid TUI crash when navigating in the annotation of recursive functions 2022-01-10 15:47:30 -03:00
util perf record ibs: Warn about sampling period skew 2022-06-24 13:18:22 -03:00
.gitignore perf tools: Delete perf-with-kcore.sh script 2022-04-27 20:11:26 -03:00
Build
builtin-annotate.c perf annotate: Add --percent-limit option 2022-05-10 14:37:55 -03:00
builtin-bench.c perf bench: Add breakpoint benchmarks 2022-05-13 11:00:38 -03:00
builtin-buildid-cache.c perf record: Disable debuginfod by default 2022-01-15 17:41:25 -03:00
builtin-buildid-list.c perf tools: Remove repipe argument from perf_session__new() 2021-08-02 10:06:51 -03:00
builtin-c2c.c perf c2c: Fix sorting in percent_rmt_hitm_cmp() 2022-06-03 21:40:15 +02:00
builtin-config.c
builtin-daemon.c perf daemon: Remove duplicate sys/file.h include 2021-10-08 15:14:50 -03:00
builtin-data.c perf data: Don't mention --to-ctf if it's not supported 2022-02-22 21:23:08 -03:00
builtin-diff.c perf tools: Remove repipe argument from perf_session__new() 2021-08-02 10:06:51 -03:00
builtin-evlist.c perf tools: Remove repipe argument from perf_session__new() 2021-08-02 10:06:51 -03:00
builtin-ftrace.c perf evlist: Rename cpus to user_requested_cpus 2022-04-01 16:19:35 -03:00
builtin-help.c
builtin-inject.c perf record: Add finished init event 2022-06-23 11:54:22 -03:00
builtin-kallsyms.c
builtin-kmem.c perf tools: Enhance the matching of sub-commands abbreviations 2022-03-26 10:55:57 -03:00
builtin-kvm.c perf kvm report: Add guest_code support 2022-05-23 10:19:15 -03:00
builtin-list.c perf list: Display hybrid PMU events with cpu type 2021-10-25 13:47:42 -03:00
builtin-lock.c perf lock: Change to synthesize task events 2022-06-03 21:26:48 +02:00
builtin-mem.c perf tools: Enhance the matching of sub-commands abbreviations 2022-03-26 10:55:57 -03:00
builtin-probe.c perf namespaces: Add functions to access nsinfo 2022-02-11 14:31:22 -03:00
builtin-record.c perf record: Add finished init event 2022-06-23 11:54:22 -03:00
builtin-report.c perf report: Set PERF_SAMPLE_DATA_SRC bit for Arm SPE event 2022-04-22 18:39:34 -03:00
builtin-sched.c perf tools: Enhance the matching of sub-commands abbreviations 2022-03-26 10:55:57 -03:00
builtin-script.c perf script: Add some missing event dumps 2022-06-23 11:54:22 -03:00
builtin-stat.c perf stat: Add requires_cpu flag for uncore 2022-05-26 12:36:57 -03:00
builtin-timechart.c perf tools: Enhance the matching of sub-commands abbreviations 2022-03-26 10:55:57 -03:00
builtin-top.c perf evlist: Rename cpus to user_requested_cpus 2022-04-01 16:19:35 -03:00
builtin-trace.c Merge remote-tracking branch 'torvalds/master' into perf/core 2022-02-17 18:40:54 -03:00
builtin-version.c perf version: Add HAVE_DEBUGINFOD_SUPPORT to built-in features 2022-04-20 13:32:09 -03:00
builtin.h
check-headers.sh tools arm64: Import cputype.h 2022-03-26 10:53:45 -03:00
command-list.txt
CREDITS
design.txt perf design.txt: Synchronize the definition of enum perf_hw_id with code 2021-11-13 18:11:50 -03:00
Makefile
Makefile.config perf build: Stop using __weak bpf_map_create() to handle older libbpf versions 2022-05-26 12:36:56 -03:00
Makefile.perf perf record: Enable off-cpu analysis with BPF 2022-05-26 12:36:57 -03:00
MANIFEST perf MANIFEST: Add bpftool files to allow building with BUILD_BPF_SKEL=1 2021-11-07 15:39:28 -03:00
perf-archive.sh
perf-completion.sh
perf-iostat.sh
perf-read-vdso.c
perf-sys.h
perf.c perf tools: Add external commands to list-cmds 2022-04-09 14:21:00 -03:00
perf.h