Messages in this thread | | | Date | Mon, 1 Nov 2004 15:06:30 +0100 | From | Ingo Molnar <> | Subject | Re: [Fwd: Re: [patch] Real-Time Preemption, -RT-2.6.9-mm1-V0.4] |
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* Ingo Molnar <mingo@elte.hu> wrote:
> > removing the poll() lines doesnt seem to impact the quality of the > > data, but i still see roughly 50 usecs added to the 'real' latency > > that i see in traces. > > this i think is related to what Thomas observed, that there's a new > irqs-off critical section somewhere. (it's in the new priority > handling code i think.)
ah, found it. Only RT tasks were supposed to get special priority handling, while in fact all tasks got it - so when Thomas ran hackbench (Thomas, you did, right?) it created an O(nr_hackbench) overhead within the mutex code ... I've uploaded -V0.6.5 to the usual place:
http://redhat.com/~mingo/realtime-preempt/
Thomas, can you confirm that this kernel fixes the irqs-off latencies? (the priority loop indeed was done with irqs turned off.)
i'm not sure this fix is related to the deadlocks reported though.
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