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Message-ID: <CAM9d7cj676sty01zqJVyk9DVesVYNFgVTZ329X=UP3xgV2aDfA@mail.gmail.com> Date: Thu, 30 May 2024 23:37:19 -0700 From: Namhyung Kim <namhyung@...nel.org> To: weilin.wang@...el.com Cc: Ian Rogers <irogers@...gle.com>, Arnaldo Carvalho de Melo <acme@...nel.org>, Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...hat.com>, Alexander Shishkin <alexander.shishkin@...ux.intel.com>, Jiri Olsa <jolsa@...nel.org>, Adrian Hunter <adrian.hunter@...el.com>, Kan Liang <kan.liang@...ux.intel.com>, linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org, Perry Taylor <perry.taylor@...el.com>, Samantha Alt <samantha.alt@...el.com>, Caleb Biggers <caleb.biggers@...el.com> Subject: Re: [RFC PATCH v10 0/8] TPEBS counting mode support Hello, On Tue, May 28, 2024 at 11:43 PM <weilin.wang@...el.com> wrote: > > From: Weilin Wang <weilin.wang@...el.com> > > I have tried not to count retire_latency events but did not succeed. > In particular, I tried the following methods: > - Convert retire_latency event to dummy event in event parser. > - Early bail out in evsel__open_cpu() and store_evsel_ids(). > > The first method fails and causes non-retire_latency events with the same event > name return 0 count. > > The second method fails and causes all the events in the same group returning > "<not counted>" results. Can you please describe where it fails? Is it failing on other events because the tpebs event is a leader of the group? I think you wanted to avoid having it in the leader position. If we can skip any actual operations (open/close/enable/disable/read) for the tpebs events, then it could be fine.. Thanks, Namhyung > > Because of above, the retire_latency event will still run in counting mode. > > Other changes in v10: > - Change perf record fork from perf stat to evsel. All the major operations > like tpebs start, stop, read_evsel should directly work through evsel. > - Make intel-tpebs x86_64 only. This change is cross-compiled to arm64. > - Put tpebs code to intel-tepbs and simplify intel-tpebs APIs to minimum number > of functions and variables. Update funtion name and variable names to use > consistent prefix. Also improve error handling. > - Integrate code patch from Ian for the :R parser. > - Update MTL metrics to TMA 4.8. > > V9: https://lore.kernel.org/all/20240521173952.3397644-1-weilin.wang@intel.com/ > > Changes in v9: > - Update the retire_latency result print and metric calculation method. Plugin > the value to evsel so that no special code is required. > - Update --control:fifo to use pipe instead of named pipe. > - Add test for TPEBS counting mode. > - Update Document with more details. > > Changes in v8: > - In this revision, the code is updated to base on Ian's patch on R modifier > parser https://lore.kernel.org/lkml/20240428053616.1125891-3-irogers@google.com/ > After this change, there is no special code required for R modifier in > metricgroup.c and metricgroup.h files. > > Caveat of this change: > Ideally, we will need to add special handling to skip counting events with R > modifier in evsel. Currently, this is not implemented so the event with :R will > be both counted and sampled. Usually, in a metric formula that uses retire_latency, > it would already require to count the event. As a result, we will endup count the > same event twice. This should be able to be handled properly when we finalize our > design on evsel R modifier support. > > - Move TPEBS specific code out from main perf stat code to separate files in > util/intel-tpebs.c and util/intel-tpebs.h. [Namhyung] > - Use --control:fifo to ack perf stat from forked perf record instead of sleep(2) [Namhyung] > - Add introductions about TPEBS and R modifier in Documents. [Namhyung] > > > Changes in v7: > - Update code and comments for better code quality [Namhyung] > - Add a separate commit for perf data [Namhyung] > - Update retire latency print function to improve alignment [Namhyung] > > Changes in v6: > - Update code and add comments for better code quality [Namhyung] > - Remove the added fd var and directly pass the opened fd to data.file.fd [Namhyung] > - Add kill() to stop perf record when perf stat exists early [Namhyung] > - Add command opt check to ensure only start perf record when -a/-C given [Namhyung] > - Squash commits [Namhyung] > > Changes in v5: > - Update code and add comments for better code quality [Ian] > > Changes in v4: > - Remove uncessary debug print and update code and comments for better > readability and quality [Namhyung] > - Update mtl metric json file with consistent TmaL1 and TopdownL1 metricgroup > > Changes in v3: > - Remove ':' when event name has '@' [Ian] > - Use 'R' as the modifier instead of "retire_latency" [Ian] > > Changes in v2: > - Add MTL metric file > - Add more descriptions and example to the patch [Arnaldo] > > Here is an example of running perf stat to collect a metric that uses > retire_latency value of event MEM_INST_RETIRED.STLB_HIT_STORES on a MTL system. > > In this simple example, there is no MEM_INST_RETIRED.STLB_HIT_STORES sample. > Therefore, the MEM_INST_RETIRED.STLB_HIT_STORES:p count and retire_latency value > are all 0. > > ./perf stat -M tma_dtlb_store -a -- sleep 1 > > [ perf record: Woken up 1 times to write data ] > [ perf record: Captured and wrote 0.000 MB - ] > > Performance counter stats for 'system wide': > > 181,047,168 cpu_core/TOPDOWN.SLOTS/ # 0.6 % tma_dtlb_store > 3,195,608 cpu_core/topdown-retiring/ > 40,156,649 cpu_core/topdown-mem-bound/ > 3,550,925 cpu_core/topdown-bad-spec/ > 117,571,818 cpu_core/topdown-fe-bound/ > 57,118,087 cpu_core/topdown-be-bound/ > 69,179 cpu_core/EXE_ACTIVITY.BOUND_ON_STORES/ > 4,582 cpu_core/MEM_INST_RETIRED.STLB_HIT_STORES/ > 30,183,104 cpu_core/CPU_CLK_UNHALTED.DISTRIBUTED/ > 30,556,790 cpu_core/CPU_CLK_UNHALTED.THREAD/ > 168,486 cpu_core/DTLB_STORE_MISSES.WALK_ACTIVE/ > 0.00 MEM_INST_RETIRED.STLB_HIT_STORES:p 0 0 > > 1.003105924 seconds time elapsed > > v1: > TPEBS is one of the features provided by the next generation of Intel PMU. > Please refer to Section 8.4.1 of "Intel® Architecture Instruction Set Extensions > Programming Reference" [1] for more details about this feature. > > This set of patches supports TPEBS in counting mode. The code works in the > following way: it forks a perf record process from perf stat when retire_latency > of one or more events are used in a metric formula. Perf stat would send a > SIGTERM signal to perf record before it needs the retire latency value for > metric calculation. Perf stat will then process sample data to extract the > retire latency data for metric calculations. Currently, the code uses the > arithmetic average of retire latency values. > > [1] https://www.intel.com/content/www/us/en/content-details/812218/intel-architecture-instruction-set-extensions-programming-reference.html?wapkw=future%20features > > > Ian Rogers (1): > perf parse-events: Add a retirement latency modifier > > Weilin Wang (7): > perf data: Allow to use given fd in data->file.fd > perf stat: Fork and launch perf record when perf stat needs to get > retire latency value for a metric. > perf stat: Plugin retire_lat value from sampled data to evsel > perf vendor events intel: Add MTL metric json files > perf stat: Add command line option for enabling tpebs recording > perf Document: Add TPEBS to Documents > perf test: Add test for Intel TPEBS counting mode > > tools/perf/Documentation/perf-list.txt | 1 + > tools/perf/Documentation/topdown.txt | 30 + > tools/perf/arch/x86/util/evlist.c | 6 + > tools/perf/builtin-stat.c | 8 + > .../arch/x86/meteorlake/metricgroups.json | 140 + > .../arch/x86/meteorlake/mtl-metrics.json | 2595 +++++++++++++++++ > .../perf/tests/shell/test_stat_intel_tpebs.sh | 19 + > tools/perf/util/Build | 1 + > tools/perf/util/data.c | 7 +- > tools/perf/util/evsel.c | 26 + > tools/perf/util/evsel.h | 6 + > tools/perf/util/intel-tpebs.c | 397 +++ > tools/perf/util/intel-tpebs.h | 48 + > tools/perf/util/parse-events.c | 2 + > tools/perf/util/parse-events.h | 1 + > tools/perf/util/parse-events.l | 3 +- > 16 files changed, 3288 insertions(+), 2 deletions(-) > create mode 100644 tools/perf/pmu-events/arch/x86/meteorlake/metricgroups.json > create mode 100644 tools/perf/pmu-events/arch/x86/meteorlake/mtl-metricsjson > create mode 100755 tools/perf/tests/shell/test_stat_intel_tpebs.sh > create mode 100644 tools/perf/util/intel-tpebs.c > create mode 100644 tools/perf/util/intel-tpebs.h > > -- > 2.43.0 >
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