Messages in this thread | | | From | Con Kolivas <> | Subject | Re: [PATCH] mm: Implement swap prefetching tweaks | Date | Sat, 11 Mar 2006 15:34:52 +1100 |
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On Saturday 11 March 2006 15:28, Peter Williams wrote: > Con Kolivas wrote: > > Because despite what anyone seems to want to believe, reading from disk > > hurts. Why it hurts so much I'm not really sure, but it's not a SCSI vs > > IDE with or without DMA issue. It's not about tweaking parameters. It > > doesn't seem to be only about cpu cycles. This is not a mistuned system > > that it happens on. It just plain hurts if we do lots of disk i/o, > > perhaps it's saturating the bus or something. Whatever it is, as much as > > I'd _like_ swap prefetch to just keep working quietly at ultra ultra low > > priority, the disk reads that swap prefetch does are not innocuous so I > > really do want them to only be done when nothing else wants cpu.
I didn't make it clear here the things affected are not even doing any I/O of their own. It's not about I/O resource allocation. However they are using 100% cpu and probably doing a lot of gpu bus traffic.
> Would you like to try a prototype version of the soft caps patch I'm > working on to see if it will help?
What happens if it's using .01% cpu and spends most of its time in uninterruptible sleep?
Cheers, Con - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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