Date: Sat, 7 Dec 2002 13:40:31 -0800 (PST) From: Ian Dowse <iedowse@FreeBSD.org> To: cvs-committers@FreeBSD.org, cvs-all@FreeBSD.org Subject: cvs commit: src/sbin/fsck_ffs fsutil.c Message-ID: <200212072140.gB7LeV80048441@repoman.freebsd.org>
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iedowse 2002/12/07 13:40:31 PST
Modified files:
sbin/fsck_ffs fsutil.c
Log:
Slow down the operation of background fsck so as to leave some disk
bandwidth for other processes. Since the sleeping is done from
userland, this avoids the locking issues that affected the kernel
version.
The algorithm used here is to measure a moving average of the times
taken by a sample of read operations and then delay 1 in 8 reads
by 16 times the measured average. This should correspond to a factor
of 3 slowdown, but in practice the factor is larger (3.5 to 4) due
to hz rounding effects.
Reviewed by: mckusick
Approved by: re
Revision Changes Path
1.20 +46 -1 src/sbin/fsck_ffs/fsutil.c
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