Messages in this thread | | | Date | Mon, 2 Aug 2004 11:28:55 +0200 | From | Ingo Molnar <> | Subject | Re: [patch] voluntary-preempt-2.6.8-rc2-M5 |
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* Lee Revell <rlrevell@joe-job.com> wrote:
> Can you post this patch, or add it to the voluntary preempt series? > The one posted several weeks ago worked for me but had to be applied > manually and has probably been improved since. > > Just to clarify the last numbers I posted were for O2.
i've uploaded the preempt-timing patch (relative to -O2):
http://redhat.com/~mingo/voluntary-preempt/preempt-timing-on-2.6.8-rc2-O2
QuickStart for those who havent used it yet: enable PREEMPT_TIMING in .config and add preempt_thresh=1000 [== 1000 usec threshold] to the kernel's boot options.
i changed the original patch to make it a bit more usable - the threshold can be changed runtime via /proc/sys/kernel/preempt_thresh, and the units are microseconds not milliseconds.
the timings should be pretty accurate in vp=0,1,2,3 modes as well.
Note that this patch only measures latencies of critical sections (preempt-off sections), not other latencies that occur when running !CONFIG_PREEMPT or with kernel_preemption=0.
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