[alsa-devel] MIDI playback not keeping steady time with recent kernels
arthur.marsh at internode.on.net
Wed Feb 9 01:51:26 CET 2011
Clemens Ladisch wrote, on 09/02/11 02:10:
> Arthur Marsh wrote:
>> OK, I applied this patch.
>> When the MIDI file was playing:
>> I still experienced some slow-down and speed-up under heavy load.
> Is "some" less than previously?
The amount of slow-down appears to be less than previously.
> It shouldn't be possible to get a speed-up; this looks as if your
> computer's clock is not stable. Are you using an NTP daemon?
To clarify, the speed-up is back to original tempo, and yes I'm using an
NTP daemon. There has been an issue of the pc not keeping accurate time
under GNU/Linux even with ntpd running and using an NTP server a few
> What kind of heave load is this? Does the same happen if you execute
> "yes | tail" in a shell?
The load when I experienced this problem was about 4 or 5, and mainly
seemed to be tied to activities that caused swapping (e.g. running
aptitude -u when other applications were using all available memory and
After quitting some applications so that there was no swapping going on
(kswapd0 showing 0.0 cpu), the MIDI file played fine, even with
Adding aptitude -u to the mix, which resulted in kswapd0 running at 4 to
10 percent cpu, caused a slow-down.
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