From: Lee Revell <rlrevell@joe-job.com>
To: Ingo Molnar <mingo@elte.hu>
Cc: Mark Knecht <markknecht@gmail.com>, lkml <linux-kernel@vger.kernel.org>
Subject: Re: 2.6.14-rt1 - xruns in a certain circumstance
Date: Mon, 31 Oct 2005 11:18:47 -0500 [thread overview]
Message-ID: <1130775527.32101.37.camel@mindpipe> (raw)
In-Reply-To: <20051031142204.GA6136@elte.hu>
On Mon, 2005-10-31 at 15:22 +0100, Ingo Molnar wrote:
> this could be some sort of hardware latency, as Lee suspects.
> Videocards are known to be pretty agressively holding the system bus,
> for the last few percentiles of Quake performance ... Also, mainboard
> chipsets are sometimes not that good at enforcing fairness between DMA
> agents - possibly starving the CPU itself for lengthly amounts of
> time. We have seen such incidents before, and latency tracing ought to
> be able to show this with reasonable certainty.
Ingo,
IIRC when I had this problem with the via X driver the latency traces
actually didn't show anything useful. The disk controller induced DMA
starvation problems did show up in the tracer.
Lee
next prev parent reply other threads:[~2005-10-31 16:36 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-10-31 2:28 2.6.14-rt1 - xruns in a certain circumstance Mark Knecht
2005-10-31 6:49 ` Lee Revell
2005-10-31 14:22 ` Ingo Molnar
2005-10-31 16:18 ` Lee Revell [this message]
2005-10-31 15:10 ` K.R. Foley
2005-10-31 15:26 ` Mark Knecht
2005-10-31 15:35 ` K.R. Foley
2005-10-31 16:39 ` Lee Revell
2005-10-31 17:38 ` Mark Knecht
2005-10-31 23:22 ` Mark Knecht
2005-11-01 1:48 ` Nuno Silva
2005-11-01 7:37 ` Lee Revell
2005-11-01 7:54 ` Lee Revell
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