low(er) disk performance with sched_4bsd then with sched_ule

Oliver Lehmann lehmann at ans-netz.de
Wed Sep 14 13:20:00 PDT 2005

Scott Long wrote:

> Oliver Lehmann wrote:
> > Any idea where the 30MB/sec drawback comes from and if I missed sth.?
> > I mean why there are 30MB/s more or less is worth to think about imho.
> > 
> Indeed.  This definitely warrants much more testing and investigation. 
> My best guess is that ULE is allowing the uio copies of the data between
> kernel and userland to complete with fewer interruptions.  It could also
> be better about keeping the threads from ping-ponging between CPUs.  Can
> you retest with different block sizes, ranging from 4k to 1m?


btw. the RAID strip size is 64k

 Oliver Lehmann

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