From: Carsten Emde <C.Emde@osadl.org>
To: Stanislav Meduna <stano@meduna.org>
Cc: Linux RT Users <linux-rt-users@vger.kernel.org>
Subject: Re: How to find long execution times in kernel threads?
Date: Tue, 30 Apr 2013 18:52:01 +0200 [thread overview]
Message-ID: <517FF6B1.9050204@osadl.org> (raw)
In-Reply-To: <517FCBA3.1000909@meduna.org>
Stano,
> I am experimenting with the cyclictest on a system running
> several RT threads to find out where some latencies are
> coming from and to get a better undertanding how the system
> behaves.
>[..]
> Basically I'd like to trace what happened between a particular
> process (not the highest priority one) was woken up until
> it got scheduled, and stop if this took longer than some
> defined time. Can this be done with the current tracing
> infrastructure?
Sure, record everything (trace-cmd record -e all) and analyze the
traces. Use kernelshark, if you prefer a GUI. I wrote a blog article on
this topic about three years ago:
https://www.osadl.org/Single-View.111+M5dc445b8ee7.0.html
Once you get an idea what is going on and which traces, events and/or
processes are particularly interesting, you may filter the recording
(trace-cmd record --help) in order to focus on your case and to reduce
Heisenberg.
Hope this helps,
-Carsten.
next prev parent reply other threads:[~2013-04-30 16:56 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-04-30 13:48 How to find long execution times in kernel threads? Stanislav Meduna
2013-04-30 16:52 ` Carsten Emde [this message]
2013-04-30 18:02 ` Stanislav Meduna
2013-05-01 3:58 ` Ashoka K
2013-05-01 7:37 ` Carsten Emde
2013-05-01 8:19 ` Stanislav Meduna
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