linux-kernel - Re: [PATCH v2] perf/core: Optimize event reschedule for a PMU

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Message-ID: <CAM9d7ch=-cp-wxLUXf1=EizAeHMG_zneSqp0owdbKp__K0ZeCw@mail.gmail.com>
Date: Sun, 4 Aug 2024 23:39:18 -0700
From: Namhyung Kim <namhyung@...nel.org>
To: Peter Zijlstra <peterz@...radead.org>
Cc: "Liang, Kan" <kan.liang@...ux.intel.com>, Ingo Molnar <mingo@...nel.org>, 
	Mark Rutland <mark.rutland@....com>, 
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>, 
	Arnaldo Carvalho de Melo <acme@...nel.org>, LKML <linux-kernel@...r.kernel.org>, 
	Ravi Bangoria <ravi.bangoria@....com>, Stephane Eranian <eranian@...gle.com>, 
	Ian Rogers <irogers@...gle.com>, Mingwei Zhang <mizhang@...gle.com>
Subject: Re: [PATCH v2] perf/core: Optimize event reschedule for a PMU

On Sat, Aug 3, 2024 at 10:08 AM Namhyung Kim <namhyung@...nel.org> wrote:
>
> On Sat, Aug 3, 2024 at 3:32 AM Peter Zijlstra <peterz@...radead.org> wrote:
> >
> > On Fri, Aug 02, 2024 at 09:11:23PM +0200, Peter Zijlstra wrote:
> >
> > > But I'll have to continue staring at this later.
> >
> > OK, I have the below, which boots and seems able to do:
> >
> >   perf stat -ae power/energy-pkg/ -- sleep 1
> >
> > and
> >
> >   perf top
> >
> > also still works, so it must be perfect, right, right?
>
> I really hope so. :)  I'll test it over the weekend.

I found a failing test about the context time - it complained about
difference in enabled vs running time of a software event.

Thanks,
Namhyung


$ perf test -v times
 46: Event times:
--- start ---
test child forked, pid 325425
Using CPUID GenuineIntel-6-55-7
...
attaching to current thread as disabled
Opening: cpu-clock:u
------------------------------------------------------------
perf_event_attr:
  type                             1 (software)
  size                             136
  config                           0 (PERF_COUNT_SW_CPU_CLOCK)
  read_format                      TOTAL_TIME_ENABLED|TOTAL_TIME_RUNNING
  disabled                         1
  exclude_kernel                   1
  exclude_hv                       1
  exclude_guest                    1
------------------------------------------------------------
sys_perf_event_open: pid 325425  cpu -1  group_fd -1  flags 0x8 = 3
  FAILED: ena 1026, run 881

attaching to CPU 0 as enabled
Opening: cpu-clock:u
------------------------------------------------------------
perf_event_attr:
  type                             1 (software)
  size                             136
  config                           0 (PERF_COUNT_SW_CPU_CLOCK)
  read_format                      TOTAL_TIME_ENABLED|TOTAL_TIME_RUNNING
  disabled                         1
  exclude_kernel                   1
  exclude_hv                       1
  exclude_guest                    1
------------------------------------------------------------
sys_perf_event_open: pid -1  cpu 0  group_fd -1  flags 0x8 = 3
  FAILED: ena 6554, run 6079
...