Re: PREEMPT_RT and latency_trace

From: Ingo Molnar
Date: Mon Jul 11 2005 - 00:04:33 EST



* Serge Noiraud <serge.noiraud@xxxxxxxx> wrote:

> Hi,
>
> I have a big dilemna on one machine :
> I run a task with RT priority which make a loop to mesure the system
> perturbation.
> It works well except on one machine.
> On a multi-cpu, If I run the program on cpu 1, I get 23us. It's OK.
> If I run the same program on cpu 0, I get 17373us !

could you try the -51-24 (or later) kernel, does it have any better
latencies? It has a PI fix that fixes the recent priority leakage
observed on SMP systems. The priority leakage can lead to excessive
delays in RT apps.

Ingo
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