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    SubjectRe: 2.6.24-rt1: timing problems (was [git pull] x86/hrtimer/acpi fixes)
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    On Sat, 2008-01-26 at 17:59 -0800, Fernando Lopez-Lezcano wrote:

    > Hi Ingo... back to testing.
    > History:
    >
    > 2.6.23.x + rt has not been very usable for audio applications.
    > 2.6.24-rt1: same so far.
    >
    > Why: Jack keeps printing "delayed..." messages and has xruns which means
    > that somehow the timing is delayed more than what jack would think
    > reasonable. As in the case with an old timing bug, the problem
    > dissapears when booting the kernel with idle=poll. Other users of Planet
    > CCRMA are able to replicate the behavior, which goes away with idle=poll
    > or booting the machine with only one core. As a workaround I have been
    > packaging 2.6.22.x but now I'm not able to use that as the old rt14
    > patch, suitably tweaked results in a non working kernel.
    >
    > So it looks like, again, timing is getting skewed when the jack process
    > jumps between cpus and thus jack sees timing jumps that are just not
    > happenning.
    >
    > This is with a build based on 2.6.24 using as a base the latest Fedora
    > rawhide source package plus 2.6.24-rt1.

    Do you have a simple testcase? (one which doesn't entail installing
    ccrma and becoming an audiophile)

    -Mike



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