Hi,

(you do have DMA enabled...)

I have tested throughput - new kernels are rather good.

I have also tested latency stuff in test9 - I have not
seen any thing as bad as your results.
But my audio apps runs with high priority...

To be able to determine the cause
Try to to renice your audio deamon (and audio clients)
 renice -10 <pid>


Did it become better?


/RogerL


Chris Evans wrote:

On Wed, 11 Oct 2000, Eric Lowe wrote:

quoted

quoted

Unfortunately, 2.4.0test9 exhibits poor streaming i/o performance when
under a bit of memory pressure.

[...]

quoted

Would you try setting /proc/sys/vm/page-cluster to 8 or 16 and let
me know the results?  I think one _part_ of the problem is that
when the swapper isn't agressive enough, it causes too much disk
thrashing which gets in the way of normal I/O... my experience
has been that with modern disks with 512K+ cache you have to
write in 64K clusters to get optimum throughput.

Raising the cluster size didn't seem to do much apart from generally slow
down interactive response. Lowering it, however, seemed to make playback
less jittery. I guess that's to be expected; faulting in large chunks of
sequential i/o won't help much when under memory pressure because the
pages will get thrown out again before they get a chance to be
used. Especially with drop_behind.

Rik what do you think.

Cheers
Chris

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