linux/drivers
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
..
acorn/char
acpi Merge branches 'release', 'bugzilla-9916', 'bugzilla-9982', 'bugzilla-9989', 'misc', 'suspend', 'thermal', 'thinkpad' and 'tsc' into release 2008-02-21 02:41:58 -05:00
amba
ata PM: Introduce PM_EVENT_HIBERNATE callback state 2008-02-23 10:40:04 -08:00
atm
auxdisplay
base Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-acpi-2.6 2008-02-21 16:33:19 -08:00
block NBD: make nbd default to deadline I/O scheduler 2008-02-23 17:12:15 -08:00
bluetooth
cdrom
char i915: fix AR register restore. 2008-02-22 16:50:29 -08:00
clocksource
connector
cpufreq cpufreq: fix kobject reference count handling 2008-02-21 15:27:06 -08:00
cpuidle
crypto
dca
dio
dma
edac
eisa
firewire
firmware dmi: don't save the same device twice 2008-02-23 17:12:14 -08:00
gpio
hid
hwmon hwmon: normal_i2c arrays should be const 2008-02-18 21:58:15 -05:00
i2c [ARM] 4827/1: fix two warnings in drivers/i2c/busses/i2c-pxa.c 2008-02-17 10:42:07 +00:00
ide PM: Introduce PM_EVENT_HIBERNATE callback state 2008-02-23 10:40:04 -08:00
ieee1394
infiniband IB/mthca: Free correct MPT on error exit from mthca_fmr_alloc() 2008-02-19 10:42:50 -08:00
input
isdn
leds
lguest
macintosh PM: Introduce PM_EVENT_HIBERNATE callback state 2008-02-23 10:40:04 -08:00
mca
md dm-raid1.c: fix NULL dereferences 2008-02-19 15:52:27 -08:00
media V4L/DVB (7219): zoran: Fix namespace conflicts with Zoran 'GPIO_MAX' enum 2008-02-18 12:18:28 -03:00
memstick
message [SCSI] mptbase: fix use-after-free's 2008-02-22 09:08:13 -06:00
mfd
misc Merge branches 'release', 'bugzilla-9916', 'bugzilla-9982', 'bugzilla-9989', 'misc', 'suspend', 'thermal', 'thinkpad' and 'tsc' into release 2008-02-21 02:41:58 -05:00
mmc
mtd
net Merge branch 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc 2008-02-21 16:18:05 -08:00
nubus
of
oprofile
parisc
parport
pci copyright owner and author clean up for intel iommu and related files 2008-02-23 17:12:14 -08:00
pcmcia PCI: drivers/pcmcia/i82092.c: fix up after pci_bus_region changes 2008-02-21 15:34:35 -08:00
pnp
power
ps3
rapidio
rtc rtc-cmos: display HPET emulation mode 2008-02-23 17:12:14 -08:00
s390 [S390] qdio: FCP/SCSI write I/O stagnates on LPAR 2008-02-19 15:29:35 +01:00
sbus
scsi Merge git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-rc-fixes-2.6 2008-02-23 12:29:16 -08:00
serial atmel_serial: fix interrupt handler return value 2008-02-23 17:12:14 -08:00
sh
sn
spi spi: pxa2xx_spi clock polarity fix 2008-02-23 17:12:14 -08:00
ssb
tc
telephony
thermal thermal: use ERR_PTR for returning error 2008-02-15 18:21:30 -05:00
uio UIO: fix Greg's stupid changes 2008-02-21 15:27:07 -08:00
usb PM: Introduce PM_EVENT_HIBERNATE callback state 2008-02-23 10:40:04 -08:00
video PM: Introduce PM_EVENT_HIBERNATE callback state 2008-02-23 10:40:04 -08:00
virtio
w1
watchdog [WATCHDOG] HP ProLiant WatchDog driver 2008-02-18 17:06:21 +00:00
xen
zorro
Kconfig
Makefile