SMP weirdness in -CURRENT

Eirik Oeverby ltning at
Tue Apr 20 06:11:38 PDT 2004


I recently upgraded my workstation to SMP, and have since experienced many of the problems that were very evident a few months ago, when I switched from SCHED_4BSD to SCHED_ULE. In the meantime many of these problems have disappeared, but now that I got my SMP system most of them have surfaced again, worse than ever.

- Jerky mouse movements, bogus mouse events
When the system is under load (i.e. during the unpack phase of building openoffice), moving the mouse (PS2, with moused) will cause very erratic movements, and bogus clicks and jumps.

- Bogus keyboard input
While typing, keypresses will be ignored, repeated n times, bogus keyboard events are generated, stuck keys, reordering of keypresses, etc. Just typing this message is a pain, I have to write real slow for the system to be able to process my keypresses

- Jerky sound
This problem is taken to a whole new level with SMP - instead of the occasional click and pop and repeating sample, it seems that WHEN such a click/pop happens, it 'sticks', that is, sound slows down to 50% speed, every sample being repeated twice. Pausing/restarting the audio stream corrects it until the next time. Playing audio during system load is completely impossible.

So.. What's going on? Am I the only one who notices these things? I have a feeling this only happens when the system load is high, not when the user load is high. And the funny thing is - my openoffice build (in this case) is running with nice -n 10, so even its priority is low.

Is this related to SCHED_ULE, should I try with SCHED_BSD? I thought the real strengths of SCHED_ULE only shows on SMP, am I wrong?

Best regards,

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