Re: [PATCH v2 00/23] PMU refactoring and improvements

From: Liang, Kan
Date: Wed May 24 2023 - 10:50:12 EST

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On 2023-05-22 2:43 a.m., Ian Rogers wrote:
> Separate the code in pmu.[ch] into the set/list of PMUs and the code
> for a particular PMU. Move the set/list of PMUs code into
> pmus.[ch]. Clean up hybrid code and remove hybrid PMU list, it is
> sufficient to scan PMUs looking for core ones. Add core PMU list and
> perf_pmus__scan_core that just reads core PMUs. Switch code that skips
> non-core PMUs during a perf_pmus__scan, to use the
> perf_pmus__scan_core variant. Don't scan sysfs for PMUs if all such
> PMUs have been previously scanned/loaded. Scanning just core PMUs, for
> the cases it is applicable, can improve the sysfs reading time by more
> than 4 fold on my laptop, as servers generally have many more uncore
> PMUs the improvement there should be larger:
>
> ```
> $ perf bench internals pmu-scan -i 1000
> Computing performance of sysfs PMU event scan for 1000 times
> Average core PMU scanning took: 989.231 usec (+- 1.535 usec)
> Average PMU scanning took: 4309.425 usec (+- 74.322 usec)
> ```
>
> The patch "perf pmu: Separate pmu and pmus" moves and renames a lot of
> functions, and is consequently large. The changes are trivial, but
> kept together to keep the overall number of patches more reasonable.
>
> v2. Address Kan's review comments wrt "cycles" -> "cycles:P" and
> "uncore_pmus" -> "other_pmus".
>
> Ian Rogers (23):
> perf tools: Warn if no user requested CPUs match PMU's CPUs
> perf evlist: Remove evlist__warn_hybrid_group
> perf evlist: Remove __evlist__add_default
> perf evlist: Reduce scope of evlist__has_hybrid
> perf pmu: Remove perf_pmu__hybrid_mounted
> perf pmu: Detect ARM and hybrid PMUs with sysfs
> perf pmu: Add is_core to pmu
> perf pmu: Rewrite perf_pmu__has_hybrid to avoid list
> perf x86: Iterate hybrid PMUs as core PMUs
> perf topology: Avoid hybrid list for hybrid topology
> perf evsel: Compute is_hybrid from PMU being core
> perf header: Avoid hybrid PMU list in write_pmu_caps
> perf metrics: Remove perf_pmu__is_hybrid use
> perf stat: Avoid hybrid PMU list
> perf mem: Avoid hybrid PMU list
> perf pmu: Remove perf_pmu__hybrid_pmus list
> perf pmus: Prefer perf_pmu__scan over perf_pmus__for_each_pmu
> perf x86 mem: minor refactor to is_mem_loads_aux_event
> perf pmu: Separate pmu and pmus
> perf pmus: Split pmus list into core and other
> perf pmus: Allow just core PMU scanning
> perf pmus: Avoid repeated sysfs scanning
> perf pmus: Ensure all PMUs are read for find_by_type

The patch set also triggers Segmentation fault with default mode on my
hybrid machine.

# ./perf stat sleep 1

Performance counter stats for 'sleep 1':

0.53 msec task-clock # 0.001 CPUs
utilized
1 context-switches # 1.875 K/sec
0 cpu-migrations # 0.000 /sec
68 page-faults # 127.476 K/sec
Segmentation fault (core dumped)

Program received signal SIGSEGV, Segmentation fault.
evsel__is_hybrid (evsel=0x55555609a1a0) at util/evsel.c:3143
3143 return pmu->is_core;
(gdb) backtrace
#0 evsel__is_hybrid (evsel=0x55555609a1a0) at util/evsel.c:3143
#1 evsel__is_hybrid (evsel=evsel@entry=0x55555609a1a0) at util/evsel.c:3135
#2 0x0000555555759468 in hybrid_uniquify (config=0x555555f931e0
<stat_config>, evsel=0x55555609a1a0)
at util/stat-display.c:813
#3 uniquify_counter (counter=0x55555609a1a0, config=0x555555f931e0
<stat_config>) at util/stat-display.c:818
#4 print_counter_aggrdata (config=config@entry=0x555555f931e0
<stat_config>,
counter=counter@entry=0x55555609a1a0, aggr_idx=aggr_idx@entry=0,
os=os@entry=0x7fffffff8fe0)
at util/stat-display.c:888
#5 0x000055555575b119 in print_counter (os=<optimized out>,
counter=<optimized out>, config=<optimized out>)
at util/stat-display.c:1019
#6 print_counter (os=0x7fffffff8fe0, counter=0x55555609a1a0,
config=0x555555f931e0 <stat_config>)
at util/stat-display.c:1009
#7 evlist__print_counters (evlist=0x555556029da0,
config=config@entry=0x555555f931e0 <stat_config>,
_target=_target@entry=0x555555f42de0 <target>, ts=ts@entry=0x0,
argc=argc@entry=2,
argv=argv@entry=0x7fffffffe1d0) at util/stat-display.c:1480
#8 0x000055555562009c in print_counters (argv=0x7fffffffe1d0, argc=2,
ts=0x0) at builtin-stat.c:979
#9 print_counters (argv=0x7fffffffe1d0, argc=2, ts=0x0) at
builtin-stat.c:971
#10 cmd_stat (argc=2, argv=0x7fffffffe1d0) at builtin-stat.c:2832
#11 0x00005555556b6670 in run_builtin (p=p@entry=0x555555f9c590
<commands+336>, argc=argc@entry=3,
argv=argv@entry=0x7fffffffe1d0) at perf.c:323
#12 0x00005555555ff2d9 in handle_internal_command (argv=0x7fffffffe1d0,
argc=3) at perf.c:377
#13 run_argv (argv=<synthetic pointer>, argcp=<synthetic pointer>) at
perf.c:421
#14 main (argc=3, argv=0x7fffffffe1d0) at perf.c:537

Thanks,
Kan
>
> tools/perf/arch/arm/util/auxtrace.c | 7 +-
> tools/perf/arch/arm/util/cs-etm.c | 4 +-
> tools/perf/arch/arm64/util/pmu.c | 6 +-
> tools/perf/arch/x86/tests/hybrid.c | 7 +-
> tools/perf/arch/x86/util/auxtrace.c | 5 +-
> tools/perf/arch/x86/util/evlist.c | 25 +-
> tools/perf/arch/x86/util/evsel.c | 27 +-
> tools/perf/arch/x86/util/intel-bts.c | 4 +-
> tools/perf/arch/x86/util/intel-pt.c | 4 +-
> tools/perf/arch/x86/util/mem-events.c | 17 +-
> tools/perf/arch/x86/util/perf_regs.c | 15 +-
> tools/perf/arch/x86/util/topdown.c | 5 +-
> tools/perf/bench/pmu-scan.c | 60 ++--
> tools/perf/builtin-c2c.c | 9 +-
> tools/perf/builtin-list.c | 4 +-
> tools/perf/builtin-mem.c | 9 +-
> tools/perf/builtin-record.c | 29 +-
> tools/perf/builtin-stat.c | 15 +-
> tools/perf/builtin-top.c | 10 +-
> tools/perf/tests/attr.c | 4 +-
> tools/perf/tests/event_groups.c | 7 +-
> tools/perf/tests/parse-events.c | 15 +-
> tools/perf/tests/parse-metric.c | 4 +-
> tools/perf/tests/pmu-events.c | 6 +-
> tools/perf/tests/switch-tracking.c | 4 +-
> tools/perf/tests/topology.c | 4 +-
> tools/perf/util/Build | 2 -
> tools/perf/util/cpumap.h | 2 +-
> tools/perf/util/cputopo.c | 16 +-
> tools/perf/util/env.c | 5 +-
> tools/perf/util/evlist-hybrid.c | 162 ---------
> tools/perf/util/evlist-hybrid.h | 15 -
> tools/perf/util/evlist.c | 67 +++-
> tools/perf/util/evlist.h | 9 +-
> tools/perf/util/evsel.c | 57 +--
> tools/perf/util/evsel.h | 3 -
> tools/perf/util/header.c | 27 +-
> tools/perf/util/mem-events.c | 17 +-
> tools/perf/util/metricgroup.c | 9 +-
> tools/perf/util/parse-events.c | 24 +-
> tools/perf/util/parse-events.y | 3 +-
> tools/perf/util/pfm.c | 6 +-
> tools/perf/util/pmu-hybrid.c | 52 ---
> tools/perf/util/pmu-hybrid.h | 32 --
> tools/perf/util/pmu.c | 482 ++------------------------
> tools/perf/util/pmu.h | 26 +-
> tools/perf/util/pmus.c | 477 ++++++++++++++++++++++++-
> tools/perf/util/pmus.h | 15 +-
> tools/perf/util/print-events.c | 15 +-
> tools/perf/util/python-ext-sources | 1 -
> tools/perf/util/stat-display.c | 21 +-
> 51 files changed, 819 insertions(+), 1032 deletions(-)
> delete mode 100644 tools/perf/util/evlist-hybrid.c
> delete mode 100644 tools/perf/util/evlist-hybrid.h
> delete mode 100644 tools/perf/util/pmu-hybrid.c
> delete mode 100644 tools/perf/util/pmu-hybrid.h
>

Next message: Neal Cardwell: "Re: [PATCH net-next 3/3] net: tcp: handle window shrink properly"
Previous message: Vladimir Oltean: "Re: [PATCH net-next 04/30] net: dsa: mt7530: improve comments regarding port 5 and 6"
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