linux/block
Jens Axboe b029195dda cfq-iosched: don't let idling interfere with plugging
When CFQ is waiting for a new request from a process, currently it'll
immediately restart queuing when it sees such a request. This doesn't
work very well with streamed IO, since we then end up splitting IO
that would otherwise have been merged nicely. For a simple dd test,
this causes 10x as many requests to be issued as we should have.
Normally this goes unnoticed due to the low overhead of requests
at the device side, but some hardware is very sensitive to request
sizes and there it can cause big slow downs.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-04-07 11:38:31 +02:00
..
as-iosched.c block: get rid of elevator_t typedef 2008-12-29 08:29:50 +01:00
blk-barrier.c block: Fix documentation for blkdev_issue_flush() 2009-01-30 12:34:37 +01:00
blk-core.c block: remove unused REQ_UNPLUG 2009-04-07 08:59:11 +02:00
blk-exec.c Add some block/ source files to the kernel-api docbook. Fix kernel-doc notation in them as needed. Fix changed function parameter names. Fix typos/spellos. In comments, change REQ_SPECIAL to REQ_TYPE_SPECIAL and REQ_BLOCK_PC to REQ_TYPE_BLOCK_PC. 2008-10-09 08:56:03 +02:00
blk-integrity.c block: Allow empty integrity profile 2009-01-30 12:34:36 +01:00
blk-ioc.c cfq-iosched: fix RCU race in the cfq io_context destructor handling 2008-05-07 09:28:57 +02:00
blk-map.c [SCSI] block: make blk_rq_map_user take a NULL user-space buffer for WRITE 2009-01-02 11:10:35 -06:00
blk-merge.c block: fix inconsistency in I/O stat accounting code 2009-04-07 08:12:38 +02:00
blk-settings.c block: use min_not_zero in blk_queue_stack_limits 2008-12-29 08:29:51 +01:00
blk-softirq.c generic-ipi: remove CSD_FLAG_WAIT 2009-02-25 14:13:44 +01:00
blk-sysfs.c block: fix inconsistency in I/O stat accounting code 2009-04-07 08:12:38 +02:00
blk-tag.c block/blk-tag.c: cleanup kernel-doc 2008-12-29 08:28:43 +01:00
blk-timeout.c block: fix deadlock in blk_abort_queue() for drivers that readd to timeout list 2009-02-18 10:34:16 +01:00
blk.h block: fix inconsistency in I/O stat accounting code 2009-04-07 08:12:38 +02:00
bsg.c bsg: Remove bogus check against request_queue->max_sectors 2009-03-26 11:01:25 +01:00
cfq-iosched.c cfq-iosched: don't let idling interfere with plugging 2009-04-07 11:38:31 +02:00
cmd-filter.c [SCSI] Make scsi.h independent of the rest of the scsi includes 2009-03-12 12:58:13 -05:00
compat_ioctl.c block: don't take lock on changing ra_pages 2008-12-29 08:28:43 +01:00
deadline-iosched.c block: get rid of elevator_t typedef 2008-12-29 08:29:50 +01:00
elevator.c block: fix inconsistency in I/O stat accounting code 2009-04-07 08:12:38 +02:00
genhd.c block: add documentation for register_blkdev() 2009-02-26 10:45:48 +01:00
ioctl.c block: don't take lock on changing ra_pages 2008-12-29 08:28:43 +01:00
Kconfig tracing/blktrace: move the tracing file to kernel/trace 2009-02-09 10:51:02 +01:00
Kconfig.iosched update I/O sched Kconfig help texts - CFQ is now default, not AS. 2007-02-17 20:08:22 +01:00
Makefile tracing/blktrace: move the tracing file to kernel/trace 2009-02-09 10:51:02 +01:00
noop-iosched.c block: get rid of elevator_t typedef 2008-12-29 08:29:50 +01:00
scsi_ioctl.c block: WARN in __blk_put_request() for potential bio leak 2009-03-26 11:01:23 +01:00