From: Peter Zijlstra <peterz@infradead.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Ze Gao <zegao2021@gmail.com>, Ingo Molnar <mingo@redhat.com>,
Namhyung Kim <namhyung@kernel.org>,
Ian Rogers <irogers@google.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Jiri Olsa <jolsa@kernel.org>, Mark Rutland <mark.rutland@arm.com>,
Masami Hiramatsu <mhiramat@kernel.org>,
Adrian Hunter <adrian.hunter@intel.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org,
linux-trace-kernel@vger.kernel.org, Ze Gao <zegao@tencent.com>
Subject: Re: [RFC PATCH 1/3] sched, tracing: report task state in symbolic chars instead
Date: Tue, 25 Jul 2023 22:16:03 +0200 [thread overview]
Message-ID: <20230725201603.GB3784071@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20230725135938.1e056a02@rorschach.local.home>
On Tue, Jul 25, 2023 at 01:59:38PM -0400, Steven Rostedt wrote:
> > @@ -232,7 +235,7 @@ TRACE_EVENT(sched_switch,
> > __array( char, prev_comm, TASK_COMM_LEN )
> > __field( pid_t, prev_pid )
> > __field( int, prev_prio )
> > - __field( long, prev_state )
> > + __field( char, prev_state )
> > __array( char, next_comm, TASK_COMM_LEN )
> > __field( pid_t, next_pid )
> > __field( int, next_prio )
>
> This will break userspace. Just because you update libtraceevent
> doesn't mean that it will get to all the users of it. There's still
> tools that have the old method hard coded and doesn't use the library.
>
> Now, because the old tools still do the parsing of this format, we can
> add a new field called prev_state_char that will give you this. Now to
> save space, we should change prev_state to int (can't make it short as
> there's that test for "+" which does sometimes happen). I believe we
> can make prev_prio and next prio into shorts (and possibly chars!).
Or just leave the thing alone?
next prev parent reply other threads:[~2023-07-25 20:17 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-25 7:22 [RFC PATCH 0/3] report task state in symbolic chars in sched tracepoints Ze Gao
2023-07-25 7:22 ` [RFC PATCH 1/3] sched, tracing: report task state in symbolic chars instead Ze Gao
2023-07-25 8:33 ` Peter Zijlstra
2023-07-25 10:53 ` Ze Gao
2023-07-25 13:31 ` Peter Zijlstra
2023-07-25 20:13 ` Steven Rostedt
2023-07-25 17:59 ` Steven Rostedt
2023-07-25 20:16 ` Peter Zijlstra [this message]
2023-07-25 21:55 ` Steven Rostedt
2023-07-26 2:48 ` Ze Gao
2023-07-26 2:41 ` Ze Gao
2023-07-25 7:22 ` [RFC PATCH 2/3] perf sched: sync with latest sched_switch tracepoint definition Ze Gao
2023-07-25 7:22 ` [RFC PATCH 3/3] libtraceevent: " Ze Gao
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=20230725201603.GB3784071@hirez.programming.kicks-ass.net \
--to=peterz@infradead.org \
--cc=acme@kernel.org \
--cc=adrian.hunter@intel.com \
--cc=alexander.shishkin@linux.intel.com \
--cc=irogers@google.com \
--cc=jolsa@kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-perf-users@vger.kernel.org \
--cc=linux-trace-kernel@vger.kernel.org \
--cc=mark.rutland@arm.com \
--cc=mhiramat@kernel.org \
--cc=mingo@redhat.com \
--cc=namhyung@kernel.org \
--cc=rostedt@goodmis.org \
--cc=zegao2021@gmail.com \
--cc=zegao@tencent.com \
/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
all inboxes | Powered by JetHome®