poor performance on big machine

Roman Divacky rdivacky at FreeBSD.org
Mon Jul 30 09:35:47 PDT 2007

On Mon, Jul 30, 2007 at 05:54:11PM +0200, Simon 'corecode' Schubert wrote:
> Simon 'corecode' Schubert wrote:
> >more data:
> >
> >- irq21 seems to always carry about half of the number of interrupts 
> >atapci1 is carrying.
> >
> >- over large periods, the % busy of ad6 is at 100%, servicing maybe 350 
> >or even 800 requests/sec.  I/O speed then is around 3-10 MB/sec.  this 
> >is with 1.10 and SMP.  I'll try compiling a old-ata kernel now.
> Okay, old ata kernel does not help.  I'd even be inclined to say "looks 
> even worse", but that might be subjective.  We definitely need an I/O 
> scheduler and a low level disk scheduler.

there's an implementation of anticipatory io scheduler for freebsd 4.3
it might be quite easily portable to dfly



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