From: Ingo Molnar <mingo@elte.hu>
To: Lee Revell <rlrevell@joe-job.com>
Cc: linux-kernel <linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@osdl.org>, "Jack O'Quin" <joq@io.com>
Subject: Re: Latency tests with 2.6.12-rc1
Date: Tue, 22 Mar 2005 09:22:22 +0100 [thread overview]
Message-ID: <20050322082222.GB9497@elte.hu> (raw)
In-Reply-To: <1111269392.15042.12.camel@mindpipe>
* Lee Revell <rlrevell@joe-job.com> wrote:
> [...] Next I tried the same test but with JACK running. The longest
> latency reported was only 200 usecs, and I did not get xruns.
>
> Then, right after I stopped JACK, the latency tracer shot up to 1645
> usecs.
>
> So there seems to be a bug in the latency tracer where the timer is
> not being reset on reschedule. If an RT task like JACK is running,
> the task does wakeup properly and the counter is reset. But if JACK
> is not running then long latencies will be reported.
hm, weird, and i have no solution for this yet. But i just found a
related bug in the -RT patch in that it reverted a latency breaker in
the ext3 path that your trace shows - affecting PREEMPT_DESKTOP. Could
you try the 40-03 patch i just uploaded (assuming it's stable for you
otherwise ...) and see whether you can still reproduce these latencies?
(if yes then please also send me a full trace via private mail, or bzip
-9 it in your public mail.)
Ingo
next prev parent reply other threads:[~2005-03-22 8:22 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-03-19 4:03 Lee Revell
2005-03-19 7:08 ` Ingo Molnar
2005-03-19 7:51 ` Lee Revell
2005-03-19 21:56 ` Lee Revell
2005-03-22 8:22 ` Ingo Molnar [this message]
2005-03-23 22:12 ` Lee Revell
2005-03-24 17:13 ` Lee Revell
2005-03-31 8:02 ` Ingo Molnar
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