Messages in this thread | | | Date | Wed, 10 Nov 2004 00:26:00 +0100 | From | Ingo Molnar <> | Subject | Re: [patch] Real-Time Preemption, -RT-2.6.10-rc1-mm3-V0.7.23 |
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* Mark_H_Johnson@raytheon.com <Mark_H_Johnson@raytheon.com> wrote:
> >i have released the -V0.7.23 Real-Time Preemption patch, which can be > >downloaded from the usual place: > > > > http://redhat.com/~mingo/realtime-preempt/ > > A few notes on results from running with this patch (well, actually > -EA that Ingo provided separately). > > [1] Build problems, separately reported to Ingo with CONFIG_PREEMPT_RT > enabled on x86 and you have modules using kunmap_atomic. Fix by adding > kunmap_virt and kmap_to_page to the list of exports.
these should be fixed in -V0.7.24 which i uploaded shortly after -V0.7.23, based on your reports. In any case, the export problems trigger with CONFIG_HIGHMEM and the affected subsystems compiled as modules.
> [2] The live lock that I was having seems to have been killed based on > an hour of testing (I could usually cause it in 5 minutes or less).
great!
> [4] Application level latencies are OK but not great. > X test - only 90% of CPU loops are within 100 usec of nominal value. > In previous RT kernels I got > 99% with 100 usec.
this might be a side-effect of the chrt-ing of events/[0|1] and/or ksoftirqd (which we did to debug the 'freeze' problems) - are those still chrt-ed? Please review and double-check all SCHED_FIFO tasks in the system and keep only those that are absolutely necessary for latencytest's operation [i.e. the soundcard IRQ and latencytest itself] - everything else should be SCHED_OTHER. Do latencies get any better if you do this?
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