[lkml]   [2004]   [Nov]   [1]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [Fwd: Re: [patch] Real-Time Preemption, -RT-2.6.9-mm1-V0.4]

* Ingo Molnar <> 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:

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.

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

 \ /
  Last update: 2005-03-22 14:07    [W:0.239 / U:5.440 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site