From: Steven Rostedt <email@example.com>
To: Stefan Metzmacher <firstname.lastname@example.org>
Cc: Ingo Molnar <email@example.com>,
Subject: Re: sched_waking vs. set_event_pid crash (Re: Tracing busy processes/threads freezes/stalls the whole machine)
Date: Fri, 23 Jul 2021 07:29:06 -0400 [thread overview]
Message-ID: <firstname.lastname@example.org> (raw)
On Fri, 23 Jul 2021 12:35:09 +0200
Stefan Metzmacher <email@example.com> wrote:
> > Assuming this does fix your issue, I sent out a real patch with the
> > explanation of what happened in the change log, so that you can see why
> > that change was your issue.
> Yes, it does the trick, thanks very much!
Can I get a "Tested-by" from you?
> Now I can finally use:
> trace-cmd record -e all -P $(pidof io_uring-cp-forever)
> But that doesn't include the iou-wrk-* threads
> and the '-c' option seems to only work with forking.
Have you tried it? It should work for threads as well. It hooks to the
sched_process_fork tracepoint, which should be triggered even when a new
thread is created.
Or do you mean that you want that process and all its threads too that are
already running? I could probably have it try to add it via the /proc file
system in that case.
Can you start the task via trace-cmd?
trace-cmd record -e all -F -c io_uring-cp-forever ...
> Is there a way to specify "trace *all* threads of the given pid"?
> (Note the threads are comming and going, so it's not possible to
> specifiy -P more than once)
Right, although, you could append tasks manually to the set_event_pid file
from another terminal after starting trace-cmd. Once a pid is added to that
file, all children it makes will also be added. That could be a work around
until we have trace-cmd do it.
Care to write a bugzilla report for this feature?
next prev parent reply other threads:[~2021-07-23 11:29 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <firstname.lastname@example.org>
2021-05-04 12:26 ` Tracing busy processes/threads freezes/stalls the whole machine Stefan Metzmacher
[not found] ` <email@example.com>
[not found] ` <firstname.lastname@example.org>
[not found] ` <email@example.com>
[not found] ` <firstname.lastname@example.org>
[not found] ` <email@example.com>
[not found] ` <firstname.lastname@example.org>
2021-07-22 22:43 ` sched_waking vs. set_event_pid crash (Re: Tracing busy processes/threads freezes/stalls the whole machine) Stefan Metzmacher
2021-07-23 1:41 ` Steven Rostedt
2021-07-23 2:51 ` Steven Rostedt
2021-07-23 10:35 ` Stefan Metzmacher
2021-07-23 11:29 ` Steven Rostedt [this message]
2021-07-23 11:53 ` Stefan Metzmacher
2021-07-23 12:41 ` Steven Rostedt
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