linux/block
Shaohua Li 7700fc4f67 CFQ: add think time check for group
Currently when the last queue of a group has no request, we don't expire
the queue to hope request from the group comes soon, so the group doesn't
miss its share. But if the think time is big, the assumption isn't correct
and we just waste bandwidth. In such case, we don't do idle.

[global]
runtime=30
direct=1

[test1]
cgroup=test1
cgroup_weight=1000
rw=randread
ioengine=libaio
size=500m
runtime=30
directory=/mnt
filename=file1
thinktime=9000

[test2]
cgroup=test2
cgroup_weight=1000
rw=randread
ioengine=libaio
size=500m
runtime=30
directory=/mnt
filename=file2

	patched		base
test1	64k		39k
test2	548k		540k
total	604k		578k

group1 gets much better throughput because it waits less time.

To check if the patch changes behavior of queue without think time. I also
tried to give test1 2ms think time or no think time. The test result is stable.
The thoughput doesn't change with/without the patch.

Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-07-12 14:24:56 +02:00
..
Kconfig kconfig: rename CONFIG_EMBEDDED to CONFIG_EXPERT 2011-01-20 17:02:05 -08:00
Kconfig.iosched blk-cgroup: config options re-arrangement 2010-04-26 19:27:56 +02:00
Makefile Merge branch 'for-2.6.37/barrier' of git://git.kernel.dk/linux-2.6-block 2010-10-22 17:07:18 -07:00
blk-cgroup.c cgroups: add per-thread subsystem callbacks 2011-05-26 17:12:34 -07:00
blk-cgroup.h cfq-iosched: Make IO merge related stats per cpu 2011-05-23 10:02:19 +02:00
blk-core.c block: avoid building too big plug list 2011-07-08 08:19:20 +02:00
blk-exec.c block: Remove 'plug/unplug' comment in blk_execute_rq_nowait 2011-05-05 15:10:05 -06:00
blk-flush.c block: hold queue if flush is running for non-queueable flush drive 2011-05-06 11:36:25 -06:00
blk-integrity.c dm: improve block integrity support 2011-04-05 23:52:43 +02:00
blk-ioc.c Merge branch 'for-linus' into for-3.1/core 2011-07-01 16:17:13 +02:00
blk-iopoll.c tree-wide: fix assorted typos all over the place 2009-12-04 15:39:55 +01:00
blk-lib.c block: eliminate potential for infinite loop in blkdev_issue_discard 2011-07-06 21:32:02 +02:00
blk-map.c block: check for proper length of iov entries earlier in blk_rq_map_user_iov() 2010-11-29 10:04:50 +01:00
blk-merge.c block: attempt to merge with existing requests on plug flush 2011-03-21 10:14:27 +01:00
blk-settings.c block: Fix discard topology stacking and reporting 2011-05-18 10:37:35 +02:00
blk-softirq.c generic-ipi: remove CSD_FLAG_WAIT 2009-02-25 14:13:44 +01:00
blk-sysfs.c Merge commit 'v2.6.39' into for-2.6.40/core 2011-05-20 20:33:15 +02:00
blk-tag.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
blk-throttle.c blk-throttle: Make total_nr_queued unsigned 2011-06-13 20:19:27 +02:00
blk-timeout.c block: ensure jiffies wrap is handled correctly in blk_rq_timed_out_timer 2010-04-21 17:42:08 +02:00
blk.h Merge branch 'for-linus' into for-2.6.40/core 2011-05-20 20:36:16 +02:00
bsg.c [SCSI] bsg: correct fault if queue object removed while dev_t open 2010-12-09 09:41:14 -06:00
cfq-iosched.c CFQ: add think time check for group 2011-07-12 14:24:56 +02:00
cfq.h blk-cgroup: Add unaccounted time to timeslice_used. 2011-03-12 16:54:00 +01:00
compat_ioctl.c compat_ioctl: fix warning caused by qemu 2011-07-01 22:32:26 +02:00
deadline-iosched.c iosched: prevent aliased requests from starving other I/O 2011-06-02 21:19:05 +02:00
elevator.c iosched: prevent aliased requests from starving other I/O 2011-06-02 21:19:05 +02:00
genhd.c block: flush MEDIA_CHANGE from drivers on close(2) 2011-07-01 16:17:47 +02:00
ioctl.c block: fix refcounting in BLKBSZSET 2011-02-24 08:54:21 -08:00
noop-iosched.c block: remove per-queue plugging 2011-03-10 08:52:07 +01:00
scsi_ioctl.c block: take care not to overflow when calculating total iov length 2010-11-10 14:40:42 +01:00