linux/fs/ext4
Frank Mayhar 0390131ba8 ext4: Allow ext4 to run without a journal
A few weeks ago I posted a patch for discussion that allowed ext4 to run
without a journal.  Since that time I've integrated the excellent
comments from Andreas and fixed several serious bugs.  We're currently
running with this patch and generating some performance numbers against
both ext2 (with backported reservations code) and ext4 with and without
a journal.  It just so happens that running without a journal is
slightly faster for most everything.

We did
	iozone -T -t 4 s 2g -r 256k -T -I -i0 -i1 -i2

which creates 4 threads, each of which create and do reads and writes on
a 2G file, with a buffer size of 256K, using O_DIRECT for all file opens
to bypass the page cache.  Results:

                     ext2        ext4, default   ext4, no journal
  initial writes   13.0 MB/s        15.4 MB/s          15.7 MB/s
  rewrites         13.1 MB/s        15.6 MB/s          15.9 MB/s
  reads            15.2 MB/s        16.9 MB/s          17.2 MB/s
  re-reads         15.3 MB/s        16.9 MB/s          17.2 MB/s
  random readers    5.6 MB/s         5.6 MB/s           5.7 MB/s
  random writers    5.1 MB/s         5.3 MB/s           5.4 MB/s 

So it seems that, so far, this was a useful exercise.

Signed-off-by: Frank Mayhar <fmayhar@google.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2009-01-07 00:06:22 -05:00
..
acl.c [PATCH] sanitize ->permission() prototype 2008-07-26 20:53:14 -04:00
acl.h ext4: Rename ext4dev to ext4 2008-10-10 20:02:48 -04:00
balloc.c ext4: Allow ext4 to run without a journal 2009-01-07 00:06:22 -05:00
bitmap.c ext4: Fix whitespace checkpatch warnings/errors 2008-09-08 22:25:24 -04:00
dir.c ext4: Fix duplicate entries returned from getdents() system call 2008-10-25 22:37:55 -04:00
ext4_extents.h Hook ext4 to the vfs fiemap interface. 2008-10-07 00:46:36 -04:00
ext4_i.h ext4: Rename ext4dev to ext4 2008-10-10 20:02:48 -04:00
ext4_jbd2.c ext4: Allow ext4 to run without a journal 2009-01-07 00:06:22 -05:00
ext4_jbd2.h ext4: Allow ext4 to run without a journal 2009-01-07 00:06:22 -05:00
ext4_sb.h ext4: Widen type of ext4_sb_info.s_mb_maxs[] 2008-12-17 00:48:39 -05:00
ext4.h ext4: remove ext4_new_blocks() and call ext4_mb_new_blocks() directly 2009-01-01 23:59:43 -05:00
extents.c ext4: Allow ext4 to run without a journal 2009-01-07 00:06:22 -05:00
file.c ext4: Rename ext4dev to ext4 2008-10-10 20:02:48 -04:00
fsync.c ext4: Add debugging markers that can be used by systemtap 2008-10-05 20:50:06 -04:00
group.h ext4: Rename read_block_bitmap() to ext4_read_block_bitmap() 2008-07-11 19:27:31 -04:00
hash.c ext4: Add support for non-native signed/unsigned htree hash algorithms 2008-10-28 13:21:44 -04:00
ialloc.c ext4: Allow ext4 to run without a journal 2009-01-07 00:06:22 -05:00
inode.c ext4: Allow ext4 to run without a journal 2009-01-07 00:06:22 -05:00
ioctl.c ext4: Allow ext4 to run without a journal 2009-01-07 00:06:22 -05:00
Kconfig fs/Kconfig: move ext2, ext3, ext4, JBD, JBD2 out 2008-10-20 11:43:59 -07:00
Makefile ext4: Rename ext4dev to ext4 2008-10-10 20:02:48 -04:00
mballoc.c ext4: Allow ext4 to run without a journal 2009-01-07 00:06:22 -05:00
mballoc.h ext4: Replace hackish ext4_mb_poll_new_transaction with commit callback 2008-10-16 20:00:24 -04:00
migrate.c ext4: Allow ext4 to run without a journal 2009-01-07 00:06:22 -05:00
namei.c ext4: Allow ext4 to run without a journal 2009-01-07 00:06:22 -05:00
namei.h [PATCH] ext4: rename ext4 symbols to avoid duplication of ext3 symbols 2006-10-11 11:14:15 -07:00
resize.c ext4: Allow ext4 to run without a journal 2009-01-07 00:06:22 -05:00
super.c ext4: Allow ext4 to run without a journal 2009-01-07 00:06:22 -05:00
symlink.c ext4: Rename ext4dev to ext4 2008-10-10 20:02:48 -04:00
xattr_security.c ext4: move headers out of include/linux 2008-04-29 18:13:32 -04:00
xattr_trusted.c ext4: remove double definitions of xattr macros 2008-07-11 19:27:31 -04:00
xattr_user.c ext4: remove double definitions of xattr macros 2008-07-11 19:27:31 -04:00
xattr.c ext4: Allow ext4 to run without a journal 2009-01-07 00:06:22 -05:00
xattr.h ext4: Rename ext4dev to ext4 2008-10-10 20:02:48 -04:00