Re: [patch] voluntary-preempt-2.6.9-rc1-bk4-R0
From: Eric St-Laurent
Date: Thu Sep 02 2004 - 22:22:13 EST
> Judging from these graphs, all of the latency issues are solved, at
> least on my UP hardware, and the latencies seem to be getting very close
> to the limits of what the hardware can do:
>
> http://krustophenia.net/testresults.php?dataset=2.6.9-rc1-Q6#/var/www/2.6.9-rc1-Q6/jack-test-1
>
> The worst case latency is only 160 usecs, and the vast majority fall
> into the pattern from 0 to 120 usecs. All of the spikes above 120 are
> almost certainly caused by netdev_max_backlog. However these are not
> long enough to cause any problems with my workload; the lowest practical
> latency for audio work is around 0.66 ms (32 frames at 48khz).
Lee,
A few weeks ago you wrote that "the worst latency I was able to trigger
was 46 usecs", now it's 160 usecs.
Ingo has done much work on his patches since then.
Why the worst latency is higher now? I presume that the latency
measurements technique are more accurate and the 46 usecs was
inaccurate?
Ref: http://uwsg.indiana.edu/hypermail/linux/kernel/0407.3/0994.html
Best regards,
Eric St-Laurent
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