linux/drivers/block
Paul Clements 48f15b93b2 NBD: make nbd default to deadline I/O scheduler
NBD doesn't work well with CFQ (or AS) schedulers, so let's default to
something else.

The two problems I have experienced with nbd and cfq are:

1) nbd hangs with cfq on RHEL 5 (2.6.18) -- this may well have been
   fixed

   There's a similar debian bug that has been filed as well:

   http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=447638

   There have been posts to nbd-general mailing list about problems with
   cfq and nbd also.

2) nbd performs about 10% better (the last time I tested) with deadline
   vs.  cfq (the overhead of cfq doesn't provide much advantage to nbd [not
   being a real disk], and you end up going through the I/O scheduler on
   the nbd server anyway, so it makes sense that deadline is better with
   nbd)

Signed-off-by: Paul Clements <paul.clements@steeleye.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-23 17:12:15 -08:00
..
aoe Merge branch 'for-linus' of git://git.kernel.dk/linux-2.6-block 2008-02-08 09:42:46 -08:00
paride
amiflop.c
ataflop.c
brd.c
cciss_cmd.h
cciss_scsi.c
cciss_scsi.h
cciss.c
cciss.h
cpqarray.c
cpqarray.h
cryptoloop.c
DAC960.c
DAC960.h
floppy.c
ida_cmd.h
ida_ioctl.h
Kconfig
loop.c
Makefile
nbd.c NBD: make nbd default to deadline I/O scheduler 2008-02-23 17:12:15 -08:00
pktcdvd.c
ps2esdi.c
ps3disk.c
smart1,2.h
sunvdc.c
swim3.c Fix compile of swim3 as module 2008-02-14 20:58:04 -08:00
sx8.c
ub.c ub: fix up the conversion to sg_init_table() 2008-02-09 11:08:33 -08:00
umem.c
umem.h
viodasd.c
virtio_blk.c
xd.c
xd.h
xen-blkfront.c xen: Implement getgeo for Xen virtual block device. 2008-02-21 16:19:13 -08:00
xsysace.c
z2ram.c