Re: kernel 2.4.21 , large disk write => system crawls

From: Mark Hahn (
Date: Thu Jul 03 2003 - 17:56:24 EST

> >>when i do a large disk write operation ( copy a big file for example ),
> >>the whole system becomes very busy ( system goes into 99% cpu

it's not write-specific. you can see below that you're somehow
managing to trigger roughly two interrupts per *either* bi or bo.
for a normal IDE setup, you should see one interrupt per 16-64K
under average use. it's almost like your sys somehow thinks
that it can only transfer 1 sector per interrupt!

> everytime i experience a slowdown, there's a 'big' number in the io (bo)
> column.

no, it's basically in=2*(bi+bo), as if your system somehow believes
it can only do a single sector per interrupt (PIO and -m1 perhaps?)
it should be more like 32K per interrupt.

> Jun 27 22:52:31 charlus kernel: Found and enabled local APIC!

have you tried without that?

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