Re: [patch] Real-Time Preemption, -RT-2.6.12-rc6-V0.7.48-00

From: Ingo Molnar
Date: Wed Jun 22 2005 - 17:13:54 EST

* William Weston <weston@xxxxxxxxx> wrote:

> Hi Ingo,
> Latency traces (attached) are looking a little bit better with -50-11.
> The CPU consistently seems to idle for ~200us at a time in the traces.
> Maximum wakeup latency since boot (over an hour ago) is 310us. With
> previous RT kernels, maximums would generally go over 800us.

these are all the first type of latencies, which seem to be hardware
related. Could you try to boot the UP kernel, do you see these latencies
there too? (if yes then please post those too)

> Should I apply your SMT scheduler latency fix, or is that patch for
> -mm only?

the fix is in current -RT kernels already. As can be seen from the
latency traces you got, the SMT scheduler is not causing latencies

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