svn commit: r200086 - head/sys/geom/mirror

[Will Andrews]

On Thu, Dec 03, 2009 at 10:55:33PM +0100, Pawel Jakub Dawidek wrote:
> On Thu, Dec 03, 2009 at 09:47:51PM +0000, Alexander Motin wrote:
> > Author: mav
> > Date: Thu Dec  3 21:47:51 2009
> > New Revision: 200086
> > URL: http://svn.freebsd.org/changeset/base/200086
> > 
> > Log:
> >   Change 'load' balancing mode algorithm:
> >   - Instead of measuring last request execution time for each drive and
> >   choosing one with smallest time, use averaged number of requests, running
> >   on each drive. This information is more accurate and timely. It allows to
> >   distribute load between drives in more even and predictable way.
> >   - For each drive track offset of the last submitted request. If new request
> >   offset matches previous one or close for some drive, prefer that drive.
> >   It allows to significantly speedup simultaneous sequential reads.
> >   
> >   PR:		kern/113885
> >   Reviewed by:	sobomax
> 
> Hmm, Will send me improved patch few days ago related to this
> functionality. Could you guys compare the patches, select the best one
> and commit it (or both if they serve different purposes)? I'm pretty
> occupied currently and it will take probably few weeks before I can join
> the discussion.

Mine changes the round-robin algorithm instead of the load one.  But mav's
patch uses a different method for distributing the load on the providers,
whereas mine is just a better-written version of the PR's patch.

-- 
wca
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