linux-kernel - Re: [PATCH RFC 0/3] perf: add logic to collect off-cpu samples

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: <CAP-5=fVwZfV+gNWcmEtRnkOtrvozMdXPVrZ37COHkf4BX1VPgw@mail.gmail.com>
Date: Thu, 11 Jul 2024 14:58:36 -0700
From: Ian Rogers <irogers@...gle.com>
To: Ajay Kaher <ajay.kaher@...adcom.com>, chu howard <howardchu95@...il.com>
Cc: peterz@...radead.org, mingo@...hat.com, acme@...nel.org, 
	namhyung@...nel.org, mark.rutland@....com, rostedt@...dmis.org, 
	alexander.shishkin@...ux.intel.com, jolsa@...nel.org, adrian.hunter@...el.com, 
	kan.liang@...ux.intel.com, yangjihong1@...wei.com, zegao2021@...il.com, 
	leo.yan@...ux.dev, asmadeus@...ewreck.org, siyanteng@...ngson.cn, 
	sunhaiyong@...ngson.cn, linux-perf-users@...r.kernel.org, 
	linux-kernel@...r.kernel.org, alexey.makhalov@...adcom.com, 
	vasavi.sirnapalli@...adcom.com
Subject: Re: [PATCH RFC 0/3] perf: add logic to collect off-cpu samples

On Thu, Jul 11, 2024 at 5:16 AM Ajay Kaher <ajay.kaher@...adcom.com> wrote:
>
> Add --off-cpu-kernel option to capture off-cpu sample alongwith on-cpu
> samples.
>
> off-cpu samples represent time spent by task when it was on wait queue
> (schedule out to waiting for events, blocked on I/O, locks, timers,
> paging/swapping, etc)
>
> Refer following links for more details:
> https://lpc.events/event/17/contributions/1556/
> https://www.youtube.com/watch?v=sF2faKGRnjs

Hi Ajay,

I wonder if Howard's improvements (not landed) for `perf record
--off-cpu` would solve this problem for you?
https://lore.kernel.org/lkml/20240424024805.144759-1-howardchu95@gmail.com/
Or is that approach problematic due to the use of BPF?

Thanks,
Ian

> Ajay Kaher (3):
>   perf/core: add logic to collect off-cpu sample
>   perf/record: add options --off-cpu-kernel
>   perf/report: add off-cpu samples
>
>  include/linux/perf_event.h            | 16 ++++++++++++++
>  include/uapi/linux/perf_event.h       |  3 ++-
>  kernel/events/core.c                  | 27 ++++++++++++++++++-----
>  tools/include/uapi/linux/perf_event.h |  3 ++-
>  tools/perf/builtin-record.c           |  2 ++
>  tools/perf/util/events_stats.h        |  2 ++
>  tools/perf/util/evsel.c               |  4 ++++
>  tools/perf/util/hist.c                | 31 ++++++++++++++++++++++++---
>  tools/perf/util/hist.h                |  1 +
>  tools/perf/util/record.h              |  1 +
>  tools/perf/util/sample.h              |  1 +
>  11 files changed, 81 insertions(+), 10 deletions(-)
>
> --
> 2.39.0
>