On Sat, Oct 27, 2001 at 03:14:44PM +0200, Giuliano Pochini wrote:
>
> > block: 1024 slots per queue, batch=341
> >
> > Wrote 600.00 MB in 71 seconds -> 8.39 MB/s (7.5 %CPU)
> >
> > Still very spiky, and during the write disk is uncapable of doing any
> > reads. IOW, no serious application can be started before writing has
> > finished. Shouldn't we favour reads over writes? Or is it just that
> > the elevator is not doing its job right, so reads suffer?
> >
> > procs memory swap io system cpu
> > r b w swpd free buff cache si so bi bo in cs us sy id
> > 0 1 1 0 3596 424 453416 0 0 0 40468 189 508 2 2 96
>
> 341*127K = ~40M.
>
> Batch is too high. It doesn't explain why reads get delayed so much, anyway.
>
Try modifying the elivator queue length with elvtune.
BTW, 2.2.19 has the queue lengths in the hundreds, and 2.4.xx has it in the
thousands. I've set 2.4 kernels back to the 2.2 defaults, and interactive
performance has gone up considerably. These are subjective tests though.
Mike
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This archive was generated by hypermail 2b29 : Wed Oct 31 2001 - 21:00:34 EST