Date: Sun, 12 Dec 2004 04:10:52 +0000 (UTC) From: Stephen McKay <mckay@FreeBSD.org> To: src-committers@FreeBSD.org, cvs-src@FreeBSD.org, cvs-all@FreeBSD.org Subject: cvs commit: src/sys/dev/vinum vinumrequest.c vinumvar.h Message-ID: <200412120410.iBC4Aqxd009113@repoman.freebsd.org>
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mckay 2004-12-12 04:10:52 UTC
FreeBSD src repository
Modified files: (Branch: RELENG_4)
sys/dev/vinum vinumrequest.c vinumvar.h
Log:
Merge from, um, oblivion: vinumvar.h 1.49, vinumrequest.c 1.73
When doing round-robin reads from a multi-plex volume, only switch to the
next plex if the sector to be read isn't nearby the last read sector.
Submitted by: Vsevolod Lobko <seva@ip.net.ua> via ru@
Not only does this boost multi-access performance, but surprisingly it helps
single process sequential reads on my IDE disk mirror. My guess is that the
read-a-block skip-a-block read-a-block effect of strict round-robin defeats
some sort of on-disk caching, leading to poor performance. With this patch,
longer contiguous reads from a single disk are more common.
/sbin/vinum needs to be rebuilt as this patch changes the size of struct plex.
OK'd by: grog
Revision Changes Path
1.44.2.6 +12 -4 src/sys/dev/vinum/vinumrequest.c
1.32.2.5 +9 -1 src/sys/dev/vinum/vinumvar.h
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