Messages in this thread | | | Date | Wed, 22 Jun 2005 10:24:50 +0200 | From | Ingo Molnar <> | Subject | Re: [patch] Real-Time Preemption, -RT-2.6.12-rc6-V0.7.48-00 |
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* William Weston <weston@sysex.net> wrote:
> Attached are two typical traces and the .config from my Xeon/HT box, > currently running -50-06 with a normal desktop workload (X, wmaker, > ten dockapps, several xterms, and firefox).
the second trace seems to be a cross-CPU wakeup bug. It's not completely clear from the trace what happened - but we measured the latency of a task (wmcube-3191), where the wakeup happened on CPU#0 and wmcube-3191 was queued to CPU#1 which was idle at that time. The bug is that it wasnt until timestamp 306us that this actually happened - and CPU#1 was just idling around in default_idle() for no good reason. CPU#1 should have run wmcube-3191 at around timestamp 13us.
I've uploaded the -50-07 kernel which will put some more info into the traces - could you try to repeat the measurement and get similar latencies? As i guess you already found out that you can always reset the measurement to get a new set of traces, via:
echo 0 > /proc/sys/kernel/preempt_max_latency
(it's not a problem if you send me multiple latency traces, i'll figure out which is the most useful one.)
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