Messages in this thread | | | Date | Tue, 30 Nov 2004 14:19:56 +0100 | From | Ingo Molnar <> | Subject | Re: Real-Time Preemption, -RT-2.6.10-rc2-mm3-V0.7.31-7 |
| |
* Rui Nuno Capela <rncbc@rncbc.org> wrote:
> xruntrace1-2.6.10-rc2-mm3-RT-V0.7.31-13-*.trc.gz > - the captured traces, as dumped with xruntrace1_watch.sh script.
> Each trace shows only the first XRUN occurrence on a distinct jackd > session. Every other trace were triggered and captured after > restarting jackd.
interesting - the trace shows only a latency of 20-40 usecs. Perhaps the tracing should be done over two periods?
Could you try to hack alsa_driver.c to do the gettimeofday(1,1) call for only every second case. Something like this ought to be enough:
{ static count = 0;
if (!(count++ & 1)) gettimeofday(0,1); }
(only one thread accesses this particular variable so there are no threading issues.)
with this variant there's a 50% chance that we get the trace of the last 2 poll() instances. (and there's a 50% chance that we get only 1 period covered.)
in any case, the scripts & approach seems to be almost there, i hope we only need the above change to see the true source of the xruns.
Ingo - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |