On Thu, Jul 03, 2003 at 06:56:24PM -0400, Mark Hahn wrote:
> > >>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!
The system is 90% in kernel when writing. That's bad (unless you're
maxing out your PCI busses or main memory bandwidth of course ;)
The IDE disks are most likely not running DMA.
>
> > 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.
Try:
hdparm -d1 /dev/hda
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This archive was generated by hypermail 2b29 : Mon Jul 07 2003 - 22:00:27 EST