From: Ingo Molnar <mingo@elte.hu>
To: Mark Knecht <markknecht@gmail.com>
Cc: Daniel Walker <dwalker@mvista.com>,
linux-kernel@vger.kernel.org, Lee Revell <rlrevell@joe-job.com>
Subject: Re: Latency data - 2.6.14-rc3-rt13
Date: Tue, 11 Oct 2005 13:17:00 +0200 [thread overview]
Message-ID: <20051011111700.GA15892@elte.hu> (raw)
In-Reply-To: <5bdc1c8b0510102045u7e4bc9eeld5b690b5e96c4a5f@mail.gmail.com>
* Mark Knecht <markknecht@gmail.com> wrote:
> > ( softirq-timer/0-3 |#0): new 3997 us maximum-latency critical section.
>
> So the root cause of this 4mS delay is the 250Hz timer. If I change
> the system to use the 1Khz timer then the time in this section drops,
> as expected, to 1mS.
this was a bug in the critical-section-latency measurement code of x64.
The timer irq is the one that leaves userspace running for the longest
time, between two kernel calls.
I have fixed these bugs in -rc4-rt1, could you try it? It should report
much lower latencies, regardless of PM settings.
Ingo
next prev parent reply other threads:[~2005-10-11 11:16 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-10-10 20:16 Latency data - 2.6.14-rc3-rt13 Mark Knecht
2005-10-10 20:49 ` Daniel Walker
2005-10-10 21:12 ` Mark Knecht
2005-10-10 21:28 ` Mark Knecht
2005-10-10 21:44 ` Daniel Walker
2005-10-10 22:09 ` Mark Knecht
2005-10-10 22:28 ` Daniel Walker
2005-10-10 23:33 ` Mark Knecht
2005-10-10 23:49 ` Mark Knecht
2005-10-11 3:45 ` Mark Knecht
2005-10-11 6:46 ` Steven Rostedt
2005-10-11 8:56 ` Sven-Thorsten Dietrich
2005-10-11 11:17 ` Ingo Molnar [this message]
2005-10-11 22:45 ` Mark Knecht
2005-10-12 0:02 ` Lee Revell
2005-10-12 1:09 ` Mark Knecht
2005-10-12 1:21 ` Lee Revell
2005-10-12 1:25 ` Mark Knecht
2005-10-12 6:38 ` Steven Rostedt
2005-10-12 16:18 ` Lee Revell
2005-10-12 17:03 ` Steven Rostedt
2005-10-11 3:56 ` Matan Peled
2005-10-11 4:45 ` Mark Knecht
2005-10-11 6:14 ` Ingo Molnar
2005-10-11 7:53 ` Ingo Molnar
2005-10-10 21:39 ` Daniel Walker
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