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To help with sequential read UFS performance on modern systems, increase

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the vfs.read_max default. For most systems this means going from 128 KiB
to 256 KiB, which is still very conservative and lower than what most
other operating systems use, but as a sane default should not
interfere much with existing systems.

For systems with RAID volumes and/or virtualization envirnments, where
read performance is very important, increasing this sysctl tunable to 32
or even more will demonstratively yield additional performance benefits.

If MAXPHYS ever gets bumped up, it will probably be a good idea to slave
read_max to it.
This commit is contained in:
Ivan Voras 2010-08-07 18:30:10 +00:00
parent af9ba7d805
commit 27f11235b9
1 changed files with 1 additions and 1 deletions
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2
sys/kern/vfs_cluster.c
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@ -71,7 +71,7 @@ static int write_behind = 1;
SYSCTL_INT(_vfs, OID_AUTO, write_behind, CTLFLAG_RW, &write_behind, 0,
"Cluster write-behind; 0: disable, 1: enable, 2: backed off");
static int read_max = 8;
static int read_max = 16;
SYSCTL_INT(_vfs, OID_AUTO, read_max, CTLFLAG_RW, &read_max, 0,
"Cluster read-ahead max block count");