Re: Latency data - 2.6.14-rc3-rt13

[Ingo Molnar]

* Mark Knecht <markknecht@xxxxxxxxx> 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
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