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Message-ID: <CAP-5=fXuyZbn3Jiq=RQaLTqybgji50Ko8jrpsinFqo+OOPBeRw@mail.gmail.com> Date: Tue, 12 Nov 2024 14:24:15 -0800 From: Ian Rogers <irogers@...gle.com> To: Leo Yan <leo.yan@....com> Cc: Atish Patra <atishp@...osinc.com>, linux-riscv@...ts.infradead.org, beeman@...osinc.com, Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...hat.com>, Arnaldo Carvalho de Melo <acme@...nel.org>, Namhyung Kim <namhyung@...nel.org>, Mark Rutland <mark.rutland@....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>, James Clark <james.clark@...aro.org>, Ze Gao <zegao2021@...il.com>, Weilin Wang <weilin.wang@...el.com>, Ben Gainey <ben.gainey@....com>, Dominique Martinet <asmadeus@...ewreck.org>, Junhao He <hejunhao3@...wei.com>, linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org Subject: Re: [PATCH v1 3/4] perf record: Skip don't fail for events that don't open On Tue, Nov 12, 2024 at 11:53 AM Leo Yan <leo.yan@....com> wrote: > > On Sat, Oct 26, 2024 at 05:17:57AM -0700, Ian Rogers wrote: > > > > Whilst for many tools it is an expected behavior that failure to open > > a perf event is a failure, ARM decided to name PMU events the same as > > legacy events and then failed to rename such events on a server uncore > > SLC PMU. As perf's default behavior when no PMU is specified is to > > open the event on all PMUs that advertise/"have" the event, this > > yielded failures when trying to make the priority of legacy and > > sysfs/json events uniform - something requested by RISC-V and ARM. A > > legacy event user on ARM hardware may find their event opened on an > > uncore PMU which for perf record will fail. Arnaldo suggested skipping > > such events which this patch implements. Rather than have the skipping > > conditional on running on ARM, the skipping is done on all > > architectures as such a fundamental behavioral difference could lead > > to problems with tools built/depending on perf. > > > > An example of perf record failing to open events on x86 is: > > ``` > > $ perf record -e data_read,cycles,LLC-prefetch-read -a sleep 0.1 > > Error: > > Failure to open event 'data_read' on PMU 'uncore_imc_free_running_0' which will be removed. > > The sys_perf_event_open() syscall returned with 22 (Invalid argument) for event (data_read). > > "dmesg | grep -i perf" may provide additional information. > > > > Error: > > Failure to open event 'data_read' on PMU 'uncore_imc_free_running_1' which will be removed. > > The sys_perf_event_open() syscall returned with 22 (Invalid argument) for event (data_read). > > "dmesg | grep -i perf" may provide additional information. > > > > Error: > > Failure to open event 'LLC-prefetch-read' on PMU 'cpu' which will be removed. > > The LLC-prefetch-read event is not supported. > > [ perf record: Woken up 1 times to write data ] > > [ perf record: Captured and wrote 2.188 MB perf.data (87 samples) ] > > > > $ perf report --stats > > Aggregated stats: > > TOTAL events: 17255 > > MMAP events: 284 ( 1.6%) > > COMM events: 1961 (11.4%) > > EXIT events: 1 ( 0.0%) > > FORK events: 1960 (11.4%) > > SAMPLE events: 87 ( 0.5%) > > MMAP2 events: 12836 (74.4%) > > KSYMBOL events: 83 ( 0.5%) > > BPF_EVENT events: 36 ( 0.2%) > > FINISHED_ROUND events: 2 ( 0.0%) > > ID_INDEX events: 1 ( 0.0%) > > THREAD_MAP events: 1 ( 0.0%) > > CPU_MAP events: 1 ( 0.0%) > > TIME_CONV events: 1 ( 0.0%) > > FINISHED_INIT events: 1 ( 0.0%) > > cycles stats: > > SAMPLE events: 87 > > ``` > > Thanks for James reminding me. Tested on AVA platform: > > # tree /sys/bus/event_source/devices/arm_dsu_*/events > ... > /sys/bus/event_source/devices/arm_dsu_9/events > ├── bus_access > ├── bus_cycles > ├── cycles > ├── l3d_cache > ├── l3d_cache_allocate > ├── l3d_cache_refill > ├── l3d_cache_wb > └── memory_error > > # ./perf record -- sleep 0.1 > Error: > Failure to open event 'cycles:PH' on PMU 'arm_dsu_0' which will be > removed. > cycles:PH: PMU Hardware doesn't support sampling/overflow-interrupts. > Try 'perf stat' > Error: > Failure to open event 'cycles:PH' on PMU 'arm_dsu_1' which will be > removed. > cycles:PH: PMU Hardware doesn't support sampling/overflow-interrupts. > Try 'perf stat' > ... > Error: > Failure to open event 'cycles:PH' on PMU 'arm_dsu_15' which will be > removed. > cycles:PH: PMU Hardware doesn't support sampling/overflow-interrupts. > Try 'perf stat' > [ perf record: Woken up 1 times to write data ] > [ perf record: Captured and wrote 0.008 MB perf.data (8 samples) ] > > # ./perf report --stats > > Aggregated stats: > TOTAL events: 67 > MMAP events: 40 (59.7%) > COMM events: 1 ( 1.5%) > SAMPLE events: 8 (11.9%) > KSYMBOL events: 6 ( 9.0%) > BPF_EVENT events: 6 ( 9.0%) > FINISHED_ROUND events: 1 ( 1.5%) > ID_INDEX events: 1 ( 1.5%) > THREAD_MAP events: 1 ( 1.5%) > CPU_MAP events: 1 ( 1.5%) > TIME_CONV events: 1 ( 1.5%) > FINISHED_INIT events: 1 ( 1.5%) > cycles:P stats: > SAMPLE events: 8 > > # ./perf stat -- sleep 0.1 > > Performance counter stats for 'sleep 0.1': > > 0.87 msec task-clock # 0.009 CPUs utilized > 1 context-switches # 1.148 K/sec > 0 cpu-migrations # 0.000 /sec > 52 page-faults # 59.685 K/sec > 877,835 instructions # 1.14 insn per cycle > # 0.25 stalled cycles per insn > 772,102 cycles # 886.210 M/sec > 191,914 stalled-cycles-frontend # 24.86% frontend cycles idle > 219,183 stalled-cycles-backend # 28.39% backend cycles idle > 184,099 branches # 211.307 M/sec > 8,548 branch-misses # 4.64% of all branches > > 0.101623529 seconds time elapsed > > 0.001645000 seconds user > 0.000000000 seconds sys > > Tested-by: Leo Yan <leo.yan@....com> Thanks Leo! As the Tested-by makes sense only if you've applied all 4 patches, which your testing and James' testing shows you've both done, I'll add the tags to all 4 patches. I'll do likewise with Atish, rebase and resend the patches. Thanks, Ian
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