From: Peter Zijlstra <peterz@infradead.org>
To: Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
Andi Kleen <ak@linux.intel.com>
Subject: Re: [PATCH v2 0/3] perf/core: expose thread context switch out event type to user space
Date: Fri, 23 Mar 2018 19:05:34 +0100 [thread overview]
Message-ID: <20180323180534.GD4043@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <713750a0-7cc1-0a27-7253-12ff4f3c9a8d@linux.intel.com>
On Thu, Mar 22, 2018 at 07:08:25PM +0300, Alexey Budankov wrote:
>
> Implementation of exposing context-switch-out type event as a part
> of PERF_RECORD_SWITCH[_CPU_WIDE] record.
>
> Introduced types of events assumed to be:
> a) preempt: when task->state == TASK_RUNNING
> b) yield: !preempt, encoding is done using new bit
> PERF_RECORD_MISC_SWITCH_OUT_YIELD like this:
A !preempt context switch isn't nessecarily a yield; please don't use
that name, it means something quite specific and this isn't it.
Specifically, on Linux yield() doesn't actually change task->state, so
when task->state is set !0 it _cannot_ have been yield.
I would invert the thing and call the preempt one SWITCH_OUT_PREEMPT.
next prev parent reply other threads:[~2018-03-23 18:05 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-22 16:08 [PATCH v2 0/3] perf/core: expose thread context switch out event type to user space Alexey Budankov
2018-03-22 16:11 ` [PATCH v2 1/3] perf/core: store context switch out type into Perf trace Alexey Budankov
2018-03-22 16:13 ` [PATCH v1 2/3] perf report: extend raw dump (-D) out with switch out event type Alexey Budankov
2018-03-22 16:16 ` [PATCH v2 3/3] perf script: extend misc field decoding " Alexey Budankov
2018-03-23 9:24 ` [PATCH v2 0/3] perf/core: expose thread context switch out event type to user space Jiri Olsa
2018-03-23 18:05 ` Peter Zijlstra [this message]
2018-03-23 20:38 ` Alexey Budankov
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20180323180534.GD4043@hirez.programming.kicks-ass.net \
--to=peterz@infradead.org \
--cc=acme@kernel.org \
--cc=ak@linux.intel.com \
--cc=alexander.shishkin@linux.intel.com \
--cc=alexey.budankov@linux.intel.com \
--cc=jolsa@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@redhat.com \
--cc=namhyung@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).