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Message-ID: <f762f404-626a-430f-b307-33c9da756ac3@linaro.org> Date: Wed, 13 Nov 2024 10:00:36 +0000 From: James Clark <james.clark@...aro.org> To: Ian Rogers <irogers@...gle.com>, 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>, 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 12/11/2024 10:24 pm, Ian Rogers wrote: > 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 Yep makes sense
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