kernel_optimize_test/fs
Andrew Morton fe1dcbc4f3 [PATCH] jbd: fix transaction batching
Ben points out that:

  When writing files out using O_SYNC, jbd's 1 jiffy delay results in a
  significant drop in throughput as the disk sits idle.  The patch below
  results in a 4-5x performance improvement (from 6.5MB/s to ~24-30MB/s on my
  IDE test box) when writing out files using O_SYNC.

So optimise the batching code by omitting it entirely if the process which is
doing a sync write is the same as the one which did the most recent sync
write.  If that's true, we're unlikely to get any other processes joining the
transaction.

(Has been in -mm for ages - it took me a long time to get on to performance
testing it)

Numbers, on write-cache-disabled IDE:

/usr/bin/time -p synctest -n 10 -uf -t 1 -p 1 dir-name

Unpatched:
	40 seconds
Patched:
	35 seconds
Batching disabled:
	35 seconds

This is the problematic single-process-doing-fsync case.  With multiple
fsyncing processes the numbers are AFACIT unaltered by the patch.

Aside: performance testing and instrumentation shows that the transaction
batching almost doesn't help (testing with synctest -n 1 -uf -t 100 -p 10
dir-name on non-writeback-caching IDE).  This is because by the time one
process is running a synchronous commit, a bunch of other processes already
have a transaction handle open, so they're all going to batch into the same
transaction anyway.

The batching seems to offer maybe 5-10% speedup with this workload, but I'm
pretty sure it was more important than that when it was first developed 4-odd
years ago...

Cc: "Stephen C. Tweedie" <sct@redhat.com>
Cc: Benjamin LaHaise <bcrl@kvack.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-02-05 11:06:53 -08:00
..
9p [PATCH] v9fs: fix corner cases when flushing request 2006-02-03 08:32:06 -08:00
adfs [PATCH] changing CONFIG_LOCALVERSION rebuilds too much, for no good reason 2005-11-09 07:55:57 -08:00
affs [PATCH] mutex subsystem, semaphore to mutex: VFS, ->i_sem 2006-01-09 15:59:24 -08:00
afs add loglevel to printk in fs/afs/cmservice.c 2006-01-11 01:52:40 +01:00
autofs [PATCH] capable/capability.h (fs/) 2006-01-11 18:42:13 -08:00
autofs4 [PATCH] autofs4 oops fix 2006-01-14 18:25:19 -08:00
befs remove unused fs/befs/attribute.c 2005-11-08 16:54:53 +01:00
bfs
cifs [CIFS] Remove compiler warning 2006-01-27 18:36:11 -08:00
coda [PATCH] mutex subsystem, semaphore to mutex: VFS, ->i_sem 2006-01-09 15:59:24 -08:00
configfs [PATCH] BUG_ON() Conversion in fs/configfs/ 2006-02-03 14:03:09 -08:00
cramfs
debugfs [PATCH] mutex subsystem, semaphore to mutex: VFS, ->i_sem 2006-01-09 15:59:24 -08:00
devfs [PATCH] mutex subsystem, semaphore to mutex: VFS, ->i_sem 2006-01-09 15:59:24 -08:00
devpts [PATCH] mutex subsystem, semaphore to mutex: VFS, ->i_sem 2006-01-09 15:59:24 -08:00
efs return statement cleanup - kill pointless parentheses 2006-01-15 02:37:08 +01:00
exportfs [PATCH] exportfs: add find_acceptable_alias helper 2006-01-18 19:20:28 -08:00
ext2 [PATCH] quota: fix error code for ext2_new_inode() 2006-02-03 08:32:09 -08:00
ext3 [PATCH] Fix two ext[23] uninitialized warnings 2006-02-03 08:32:05 -08:00
fat [PATCH] fat: Fix truncate() write ordering 2006-02-03 08:32:10 -08:00
freevxfs [PATCH] fix possible PAGE_CACHE_SHIFT overflows 2006-01-08 20:13:54 -08:00
fuse [PATCH] fuse: fix request_end() vs fuse_reset_request() race 2006-02-05 11:06:51 -08:00
hfs [PATCH] hfs: cleanup HFS prints 2006-01-18 19:20:23 -08:00
hfsplus [PATCH] hfs: set type/creator for symlinks 2006-01-18 19:20:23 -08:00
hostfs [PATCH] uml: hostfs - fix possible PAGE_CACHE_SHIFT overflows 2005-12-29 09:48:15 -08:00
hpfs [PATCH] mutex subsystem, semaphore to mutex: VFS, ->i_sem 2006-01-09 15:59:24 -08:00
hppfs [PATCH] mutex subsystem, semaphore to mutex: VFS, ->i_sem 2006-01-09 15:59:24 -08:00
hugetlbfs [PATCH] mm: hugepage accounting fix 2006-02-01 08:53:15 -08:00
isofs [PATCH] isofs: remove d_splice_alias NULL check from isofs_lookup 2006-01-14 18:27:12 -08:00
jbd [PATCH] jbd: fix transaction batching 2006-02-05 11:06:53 -08:00
jffs [PATCH] fs/jffs/intrep.c: 255 is unsigned char 2006-02-03 08:32:05 -08:00
jffs2 [PATCH] Unlinline a bunch of other functions 2006-01-14 18:27:06 -08:00
jfs [PATCH] capable/capability.h (fs/) 2006-01-11 18:42:13 -08:00
lockd NLM: Ensure that nlmclnt_cancel_callback() doesn't loop forever 2006-02-01 12:52:23 -05:00
minix
msdos
ncpfs [PATCH] ncpfs: remove kmalloc wrapper 2006-01-14 18:27:12 -08:00
nfs NFSv3: fix sync_retry in direct i/o NFS 2006-02-01 12:52:25 -05:00
nfs_common
nfsd [PATCH] knfsd: Restore recently broken ACL functionality to NFS server 2006-02-01 08:53:09 -08:00
nls
ntfs [PATCH] ntfs: remove superflous MS_NOATIME/MS_NODIRATIME assignments 2006-01-10 08:01:33 -08:00
ocfs2 [PATCH] ocfs2: don't wait on recovery when locking journal 2006-02-03 14:05:14 -08:00
openpromfs
partitions [PATCH] partitions: Read Rio Karma partition table 2006-01-16 23:15:29 -08:00
proc [PATCH] disable per cpu intr in /proc/stat 2006-02-03 08:32:07 -08:00
qnx4 fs/qnx4/bitmap.c: #if 0 qnx4_new_block() 2006-01-03 13:21:37 +01:00
ramfs [PATCH] NOMMU: Provide shared-writable mmap support on ramfs 2006-01-06 08:33:32 -08:00
reiserfs [PATCH] someone broke reiserfs V3 mount options, this fixes it 2006-02-03 08:32:03 -08:00
relayfs [PATCH] mutex subsystem, semaphore to mutex: VFS, ->i_sem 2006-01-09 15:59:24 -08:00
romfs [PATCH] fix possible PAGE_CACHE_SHIFT overflows 2006-01-08 20:13:54 -08:00
smbfs [PATCH] smbfs readdir vs signal fix 2006-02-01 08:53:09 -08:00
sysfs [PATCH] capable/capability.h (fs/) 2006-01-11 18:42:13 -08:00
sysv correct email address of Manfred Spraul 2006-01-15 02:43:54 +01:00
udf [PATCH] UDF: Fix issues reported by Coverity in namei.c 2006-02-03 08:32:11 -08:00
ufs [PATCH] ufs: fix hang during `rm' 2006-02-03 08:32:04 -08:00
vfat
xfs [PATCH] Direct Migration V9: Avoid writeback / page_migrate() method 2006-02-01 08:53:17 -08:00
aio.c [PATCH] rcu file: use atomic primitives 2006-01-08 20:13:48 -08:00
attr.c [PATCH] capable/capability.h (fs/) 2006-01-11 18:42:13 -08:00
bad_inode.c
binfmt_aout.c [PATCH] dump_thread() cleanup 2006-01-10 08:01:25 -08:00
binfmt_elf_fdpic.c [PATCH] fs/binfmt_elf: Remove unneeded kmalloc() return value casts 2006-01-10 08:02:01 -08:00
binfmt_elf.c [PATCH] Unlinline a bunch of other functions 2006-01-14 18:27:06 -08:00
binfmt_em86.c
binfmt_flat.c [PATCH] uclinux: delay binfmt_flat trace 2006-01-10 09:31:27 -08:00
binfmt_misc.c [PATCH] Unlinline a bunch of other functions 2006-01-14 18:27:06 -08:00
binfmt_script.c
binfmt_som.c
bio.c [BLOCK] A few kerneldoc fixups 2006-01-31 15:24:34 +01:00
block_dev.c [PATCH] mutex subsystem, semaphore to mutex: VFS, ->i_sem 2006-01-09 15:59:24 -08:00
buffer.c [PATCH] Trivial optimization of ll_rw_block() 2006-02-03 08:32:10 -08:00
char_dev.c [PATCH] convert /proc/devices to use seq_file interface 2006-01-14 18:25:19 -08:00
compat_ioctl.c [PATCH] Implement ioctl emulation for the parport character device 2006-01-12 09:08:49 -08:00
compat.c [PATCH] compat: fix compat_sys_openat and friends 2006-02-01 22:04:33 -08:00
dcache.c [PATCH] make "struct d_cookie" depend on CONFIG_PROFILING 2006-02-03 08:32:04 -08:00
dcookies.c [PATCH] capable/capability.h (fs/) 2006-01-11 18:42:13 -08:00
direct-io.c [PATCH] fix O_DIRECT read of last block in a sparse file 2006-02-03 08:32:07 -08:00
dnotify.c
dquot.c [PATCH] capable/capability.h (fs/) 2006-01-11 18:42:13 -08:00
drop_caches.c [PATCH] drop-pagecache 2006-01-08 20:12:40 -08:00
eventpoll.c
exec.c [PATCH] vfs: *at functions: core 2006-01-18 19:20:29 -08:00
fcntl.c [PATCH] fcntl F_SETFL and read-only IS_APPEND files 2006-02-03 08:32:07 -08:00
fifo.c [PATCH] mutex subsystem, semaphore to mutex: VFS, ->i_sem 2006-01-09 15:59:24 -08:00
file_table.c [PATCH] capable/capability.h (fs/) 2006-01-11 18:42:13 -08:00
file.c [PATCH] percpu data: only iterate over possible CPUs 2006-02-05 11:06:51 -08:00
filesystems.c
fs-writeback.c
inode.c [PATCH] DocBook: fix some kernel-doc comments in fs and block 2006-02-01 08:53:27 -08:00
inotify.c [PATCH] add missing syscall declarations 2006-01-18 19:20:22 -08:00
ioctl.c [PATCH] capable/capability.h (fs/) 2006-01-11 18:42:13 -08:00
ioprio.c [PATCH] capable/capability.h (fs/) 2006-01-11 18:42:13 -08:00
Kconfig o Remove confusing Kconfig text for CONFIGFS_FS. 2006-02-03 13:47:17 -08:00
Kconfig.binfmt [PATCH] frv: suppress configuration of certain features for FRV 2006-01-08 20:13:36 -08:00
libfs.c [PATCH] debugfs: hard link count wrong 2006-02-03 08:32:11 -08:00
locks.c [PATCH] tiny: Uninline some fslocks.c functions 2006-01-08 20:14:10 -08:00
Makefile [PATCH] sanitize building of fs/compat_ioctl.c 2006-01-10 08:01:33 -08:00
mbcache.c [PATCH] Unlinline a bunch of other functions 2006-01-14 18:27:06 -08:00
mpage.c [PATCH] fix possible PAGE_CACHE_SHIFT overflows 2006-01-08 20:13:54 -08:00
namei.c [PATCH] DocBook: fix some kernel-doc comments in fs and block 2006-02-01 08:53:27 -08:00
namespace.c [PATCH] add /sys/fs 2006-01-16 23:15:29 -08:00
nfsctl.c [PATCH] EDAC: atomic scrub operations 2006-01-18 19:20:30 -08:00
open.c [PATCH] vfs: *at functions: core 2006-01-18 19:20:29 -08:00
pipe.c [PATCH] Unlinline a bunch of other functions 2006-01-14 18:27:06 -08:00
pnode.c [PATCH] shared mounts: cleanup 2006-01-08 20:13:56 -08:00
pnode.h [PATCH] unbindable mounts 2005-11-07 18:18:11 -08:00
posix_acl.c
quota_v1.c
quota_v2.c [PATCH] quota_v2: printk warning fixes 2006-02-03 08:32:03 -08:00
quota.c [PATCH] capable/capability.h (fs/) 2006-01-11 18:42:13 -08:00
read_write.c [PATCH] mutex subsystem, semaphore to mutex: VFS, ->i_sem 2006-01-09 15:59:24 -08:00
readdir.c [PATCH] mutex subsystem, semaphore to mutex: VFS, ->i_sem 2006-01-09 15:59:24 -08:00
select.c [PATCH] Add pselect/ppoll system call implementation 2006-01-18 19:20:30 -08:00
seq_file.c [PATCH] allow callers of seq_open do allocation themselves 2005-11-07 18:18:09 -08:00
stat.c [PATCH] vfs: *at functions: core 2006-01-18 19:20:29 -08:00
super.c [PATCH] mutex subsystem, semaphore to mutex: VFS, sb->s_lock 2006-01-09 15:59:25 -08:00
xattr_acl.c
xattr.c [PATCH] move xattr permission checks into the VFS 2006-01-10 08:01:29 -08:00