linux-kernel - Re: [PATCH 0/5] perf: Per PMU context reschedule and misc

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CAM9d7ci7zEQUPTLLUdNci49fJHiM_6iiCn_Gpp05aEPyrJBmAg@mail.gmail.com>
Date: Wed, 7 Aug 2024 11:54:34 -0700
From: Namhyung Kim <namhyung@...nel.org>
To: Peter Zijlstra <peterz@...radead.org>
Cc: mingo@...nel.org, acme@...nel.org, mark.rutland@....com, 
	alexander.shishkin@...ux.intel.com, jolsa@...nel.org, irogers@...gle.com, 
	adrian.hunter@...el.com, kan.liang@...ux.intel.com, 
	linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 0/5] perf: Per PMU context reschedule and misc

Hi Peter,

On Wed, Aug 7, 2024 at 4:56 AM Peter Zijlstra <peterz@...radead.org> wrote:
>
> Hi,
>
> This is 'fallout' from Namhyung posting his per-pmu ctx_resched() patches. It
> started with me trying to clean up and get rid of corner cases, and then got
> involved when Kan noted the time keeping issue.
>
> Anyway, please review / test.

It works blazingly fast!

  # ./stress-pmu
  delta: 0.000307 sec (3 usec/op)

I found a problem with my patch that it called __pmu_ctx_sched_out() for
nothing (I guess is_active only has EVENT_TIME).  I thought ctx_sched_out()
would stop if it doesn't change EVENT_ALL but it iterated all PMUs anyway.

But with this change we don't need ctx_sched_out(EVENT_TIME) anymore.

Reviewed-by: Namhyung Kim <namhyung@...nel.org>

Thanks,
Namhyung