Re: 2.6.14-rt1 - xruns in a certain circumstance

[Lee Revell]

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

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