Vivek Goyal d9449ce35a Fix regression in direct writes performance due to WRITE_ODIRECT flag removal ... There seems to be a regression in direct write path due to following commit in for-2.6.33 branch of block tree. commit 1af60fbd75 Author: Jeff Moyer <jmoyer@redhat.com> Date: Fri Oct 2 18:56:53 2009 -0400 block: get rid of the WRITE_ODIRECT flag Marking direct writes as WRITE_SYNC_PLUG instead of WRITE_ODIRECT, sets the NOIDLE flag in bio and hence in request. This tells CFQ to not expect more request from the queue and not idle on it (despite the fact that queue's think time is less and it is not seeky). So direct writers lose big time when competing with sequential readers. Using fio, I have run one direct writer and two sequential readers and following are the results with 2.6.32-rc7 kernel and with for-2.6.33 branch. Test ==== 1 direct writer and 2 sequential reader running simultaneously. [global] directory=/mnt/sdc/fio/ runtime=10 [seqwrite] rw=write size=4G direct=1 [seqread] rw=read size=2G numjobs=2 2.6.32-rc7 ========== direct writes: aggrb=2,968KB/s readers : aggrb=101MB/s for-2.6.33 branch ================= direct write: aggrb=19KB/s readers aggrb=137MB/s This patch brings back the WRITE_ODIRECT flag, with the difference that we don't set the BIO_RW_UNPLUG flag so that device is not unplugged after submission of request and an explicit unplug from submitter is required. That way we fix the jeff's issue of not enough merging taking place in aio path as well as make sure direct writes get their fair share. After the fix ============= for-2.6.33 + fix ---------------- direct writes: aggrb=2,728KB/s reads: aggrb=103MB/s Thanks Vivek Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>		2009-11-26 09:46:46 +01:00
..
9p	9p: Add fscache support to 9p	2009-09-23 13:03:46 -05:00
adfs	adfs: remove redundant test on unsigned	2009-09-24 07:21:05 -07:00
affs
afs	afs: remove cache.h	2009-10-01 16:11:16 -07:00
autofs	trivial: remove unnecessary semicolons	2009-09-21 15:14:58 +02:00
autofs4	autofs4 - fix missed case when changing to use struct path	2009-08-31 17:44:05 -10:00
befs	fs: Make unload_nls() NULL pointer safe	2009-09-24 07:47:42 -04:00
bfs
btrfs	Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable	2009-10-15 15:06:37 -07:00
cachefiles
cifs	[CIFS] Fixing to avoid invalid kfree() in cifs_get_tcp_session()	2009-10-06 18:31:29 +00:00
coda	headers: remove sched.h from poll.h	2009-10-04 15:05:10 -07:00
configfs	writeback: add name to backing_dev_info	2009-09-11 09:20:26 +02:00
cramfs
debugfs
devpts	Move magic numbers into magic.h	2009-09-23 07:39:28 -07:00
dlm	dlm: fix socket fd translation	2009-09-30 12:19:44 -05:00
ecryptfs	ima: ecryptfs fix imbalance message	2009-10-08 11:31:38 -05:00
efs
exofs	exofs: remove BKL from super operations	2009-09-24 07:47:38 -04:00
exportfs
ext2	Merge branch 'hwpoison' of git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-mce-2.6	2009-09-24 07:53:22 -07:00
ext3	ext3: Don't update superblock write time when filesystem is read-only	2009-10-13 00:06:43 +02:00
ext4	Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4	2009-10-03 11:24:19 -07:00
fat	Merge git://git.kernel.org/pub/scm/linux/kernel/git/hirofumi/fatfs-2.6	2009-09-30 09:31:14 -07:00
freevxfs
fscache
fuse	const: mark struct vm_struct_operations	2009-09-27 11:39:25 -07:00
gfs2	const: mark struct vm_struct_operations	2009-09-27 11:39:25 -07:00
hfs	hfs: fix oops on mount with corrupted btree extent records	2009-10-29 07:39:29 -07:00
hfsplus	hfsplus: refuse to mount volumes larger than 2TB	2009-10-29 07:39:27 -07:00
hostfs
hpfs
hppfs
hugetlbfs	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6	2009-09-24 08:32:11 -07:00
isofs	fs: Make unload_nls() NULL pointer safe	2009-09-24 07:47:42 -04:00
jbd	jbd: Annotate transaction start also for journal_restart()	2009-09-16 17:44:10 +02:00
jbd2	const: constify remaining file_operations	2009-10-01 16:11:11 -07:00
jffs2	Merge git://git.infradead.org/mtd-2.6	2009-09-23 10:07:49 -07:00
jfs	fs: Make unload_nls() NULL pointer safe	2009-09-24 07:47:42 -04:00
lockd	headers: utsname.h redux	2009-09-23 18:13:10 -07:00
minix	V3 minixfs: add missing directory type checking	2009-09-23 07:39:57 -07:00
ncpfs	const: mark struct vm_struct_operations	2009-09-27 11:39:25 -07:00
nfs	NFSv4: The link() operation should return any delegation on the file	2009-10-26 08:09:46 -04:00
nfs_common
nfsd	const: constify remaining file_operations	2009-10-01 16:11:11 -07:00
nilfs2	const: constify remaining file_operations	2009-10-01 16:11:11 -07:00
nls	Merge git://git.kernel.org/pub/scm/linux/kernel/git/hirofumi/fatfs-2.6	2009-09-30 09:31:14 -07:00
notify	dnotify: ignore FS_EVENT_ON_CHILD	2009-10-20 18:02:33 -04:00
ntfs	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6	2009-09-24 08:32:11 -07:00
ocfs2	const: constify remaining file_operations	2009-10-01 16:11:11 -07:00
omfs	const: constify remaining file_operations	2009-10-01 16:11:11 -07:00
openpromfs
partitions	partitions: read whole sector with EFI GPT header	2009-11-23 09:29:58 +01:00
proc	hwpoison: fix/proc/meminfo alignment	2009-10-29 07:39:25 -07:00
qnx4	qnx4: remove write support	2009-09-23 07:39:30 -07:00
quota	const: make struct super_block::s_qcop const	2009-09-22 07:17:24 -07:00
ramfs	truncate: use new helpers	2009-09-24 08:41:47 -04:00
reiserfs	const: make struct super_block::s_qcop const	2009-09-22 07:17:24 -07:00
romfs	ROMFS: fix length used with romfs_dev_strnlen() function	2009-10-11 11:33:56 -07:00
smbfs	fs: Make unload_nls() NULL pointer safe	2009-09-24 07:47:42 -04:00
squashfs	const: mark remaining super_operations const	2009-09-22 07:17:24 -07:00
sysfs	sysfs: Allow sysfs_notify_dirent to be called from interrupt context.	2009-10-14 15:16:25 -07:00
sysv
ubifs	const: mark struct vm_struct_operations	2009-09-27 11:39:25 -07:00
udf	udf: Fix possible corruption when close races with write	2009-09-14 19:13:01 +02:00
ufs
xfs	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/fs/xfs/xfs	2009-10-31 12:12:49 -07:00
aio.c	block: move bdi/address_space unplug functions to backing-dev.h	2009-10-29 13:59:26 +01:00
anon_inodes.c	headers: remove sched.h from poll.h	2009-10-04 15:05:10 -07:00
attr.c	truncate: new helpers	2009-09-24 08:41:47 -04:00
bad_inode.c
binfmt_aout.c
binfmt_elf.c	elf: clean up fill_note_info()	2009-09-24 07:21:01 -07:00
binfmt_elf_fdpic.c	fdpic: ignore the loader's PT_GNU_STACK when calculating the stack size	2009-09-24 07:21:02 -07:00
binfmt_em86.c
binfmt_flat.c	flat: use IS_ERR_VALUE() helper macro	2009-09-24 07:21:03 -07:00
binfmt_misc.c
binfmt_script.c
binfmt_som.c
bio-integrity.c
bio.c	block: add helpers to run flush_dcache_page() against a bio and a request's pages	2009-11-26 09:16:19 +01:00
block_dev.c	Merge branch 'for-linus' into for-2.6.33	2009-11-03 21:14:39 +01:00
buffer.c	Merge branch 'writeback' of git://git.kernel.dk/linux-2.6-block	2009-09-25 09:27:30 -07:00
char_dev.c	fs/char_dev.c: remove useless loop	2009-09-24 07:21:03 -07:00
compat.c	fs: fix overflow in sys_mount() for in-kernel calls	2009-09-24 08:40:15 -04:00
compat_binfmt_elf.c
compat_ioctl.c	compat_ioctl: hook up compat handler for FIEMAP ioctl	2009-08-07 10:39:56 -07:00
dcache.c
dcookies.c
direct-io.c	Fix regression in direct writes performance due to WRITE_ODIRECT flag removal	2009-11-26 09:46:46 +01:00
drop_caches.c	sysctl: remove "struct file *" argument of ->proc_handler	2009-09-24 07:21:04 -07:00
eventfd.c	anonfd: split interface into file creation and install	2009-09-23 07:39:29 -07:00
eventpoll.c
exec.c	task_struct cleanup: move binfmt field to mm_struct	2009-09-24 07:21:05 -07:00
fcntl.c	fcntl: add F_[SG]ETOWN_EX	2009-09-24 07:21:01 -07:00
fifo.c
file.c	headers: remove sched.h from interrupt.h	2009-10-11 11:20:58 -07:00
file_table.c	sysctl: remove "struct file *" argument of ->proc_handler	2009-09-24 07:21:04 -07:00
filesystems.c
fs-writeback.c	writeback: pass in super_block to bdi_start_writeback()	2009-09-26 00:10:40 +02:00
fs_struct.c
generic_acl.c
inode.c	vfs: optimize touch_time() too	2009-09-24 07:47:27 -04:00
internal.h	fs: fix overflow in sys_mount() for in-kernel calls	2009-09-24 08:40:15 -04:00
ioctl.c	vfs: explicitly cast s_maxbytes in fiemap_check_ranges	2009-09-24 07:47:31 -04:00
ioprio.c
Kconfig	Merge branch 'sh/for-2.6.32' of git://git.kernel.org/pub/scm/linux/kernel/git/lethal/sh-2.6	2009-10-29 09:07:15 -07:00
Kconfig.binfmt
libfs.c	libfs: return error code on failed attr set	2009-09-24 07:47:30 -04:00
locks.c	const: make lock_manager_operations const	2009-09-22 07:17:25 -07:00
Makefile
mbcache.c
mpage.c
namei.c	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6	2009-09-11 08:55:49 -07:00
namespace.c	fs: fix overflow in sys_mount() for in-kernel calls	2009-09-24 08:40:15 -04:00
nfsctl.c
no-block.c
open.c	fs: change sys_truncate length parameter type	2009-09-23 09:21:05 -07:00
pipe.c	fs: pipe.c null pointer dereference	2009-10-22 08:11:44 +09:00
pnode.c
pnode.h
posix_acl.c
read_write.c	sendfile(): check f_op.splice_write() rather than f_op.sendpage()	2009-11-04 09:09:52 +01:00
read_write.h
readdir.c
select.c	headers: remove sched.h from poll.h	2009-10-04 15:05:10 -07:00
seq_file.c	vfs: seq_file: add helpers for data filling	2009-09-24 07:47:35 -04:00
signalfd.c
splice.c	sendfile(): check f_op.splice_write() rather than f_op.sendpage()	2009-11-04 09:09:52 +01:00
stack.c
stat.c
super.c	freeze_bdev: grab active reference to frozen superblocks	2009-09-24 07:47:41 -04:00
sync.c	fs/buffer.c: clean up EXPORT* macros	2009-09-23 07:39:29 -07:00
timerfd.c
utimes.c
xattr.c	VFS: Factor out part of vfs_setxattr so it can be called from the SELinux hook for inode_setsecctx.	2009-09-10 10:11:22 +10:00
xattr_acl.c