On Sun, 28 Feb 2010, Bill Davidsen wrote:

Justin Piszcz wrote:

quoted

[ .. ]

quoted

fdatasync:
http://lkml.indiana.edu/hypermail/linux/kernel/1002.3/01507.html

I wasn't expecting a huge change in value, your data size is large. But 
thanks, the total time without sync can be off by at least seconds, making it 
hard to duplicate results. You missed nothing this time.

Did you use any of the options with ext4? I found about 15-20% with options, 
but I didn't take good enough notes to quote now. :-(
That doesn't mean there wasn't more, I tested on FC9, ext4 was experimental 
then.

Yes:

I tried nearly every option in the ext4 readme:

more:

p63:~# tune2fs -o journal_data_writeback /dev/md0
tune2fs 1.41.10 (10-Feb-2009)
p63:~# mount /dev/md0 /r1 -o noatime,barrier=0,data=writeback,nobh,commit=100,nouser_xattr
p63:~#

p63:~# cd /r1
p63:/r1# dd if=/dev/zero of=file bs=1M count=10240
10240+0 records in
10240+0 records out
10737418240 bytes (11 GB) copied, 35.7193 s, 301 MB/s
p63:/r1#

p63:~# mount /dev/md0 /r1 -o noatime,barrier=0,data=writeback,nobh,commit=100,nouser_xattr,nodelalloc
p63:~#
p63:/r1# dd if=/dev/zero of=file bs=1M count=10240
10240+0 records in
10240+0 records out
10737418240 bytes (11 GB) copied, 30.5846 s, 351 MB/s
p63:/r1#

p63:~# mount /dev/md0 /r1 -o noatime,barrier=0,data=writeback,nobh,commit=100,nouser_xattr,nodelalloc,max_batch_time=0
p63:~#
p63:/r1# dd if=/dev/zero of=file bs=1M count=10240
10240+0 records in
10240+0 records out
10737418240 bytes (11 GB) copied, 30.8501 s, 348 MB/s
p63:/r1#

p63:~# mount /dev/md0 /r1 -o noatime,barrier=0,data=writeback,nobh,commit=100,nouser_xattr,nodelalloc,min_batch_time=10000
p63:~#
p63:/r1# dd if=/dev/zero of=file bs=1M count=10240
10240+0 records in
10240+0 records out
10737418240 bytes (11 GB) copied, 31.0127 s, 346 MB/s
p63:/r1#

p63:~# mount /dev/md0 /r1 -o noatime,barrier=0,data=writeback,nobh,commit=100,nouser_xattr,nodelalloc,journal_ioprio=0
p63:~#
p63:/r1# dd if=/dev/zero of=file bs=1M count=10240
10240+0 records in
10240+0 records out
10737418240 bytes (11 GB) copied, 31.1559 s, 345 MB/s
p63:/r1# cd


p63:~# mount /dev/md0 /r1 -o noatime,barrier=0,data=writeback,nobh,commit=100,nouser_xattr,nodelalloc,journal_ioprio=7
p63:~#
p63:/r1# dd if=/dev/zero of=file bs=1M count=10240
10240+0 records in
10240+0 records out
10737418240 bytes (11 GB) copied, 31.4713 s, 341 MB/s
p63:/r1#

p63:~# mount /dev/md0 /r1 -o noatime,barrier=0,data=writeback,nobh,commit=100,nouser_xattr,nodelalloc,journal_async_commit
p63:~#
p63:/r1# dd if=/dev/zero of=file bs=1M count=10240
10240+0 records in
10240+0 records out
10737418240 bytes (11 GB) copied, 30.7633 s, 349 MB/s
p63:/r1#

p63:~# mount /dev/md0 /r1 -o noatime,barrier=0,data=writeback,nobh,commit=100,nouser_xattr,nodelalloc,journal_async_commit,oldalloc
p63:~#
p63:/r1# dd if=/dev/zero of=file bs=1M count=10240
10240+0 records in
10240+0 records out
10737418240 bytes (11 GB) copied, 30.7607 s, 349 MB/s
p63:/r1#

p63:~# mount /dev/md0 /r1 -o noatime,barrier=0,data=writeback,nobh,commit=100,nouser_xattr,nodelalloc,journal_async_commit,stripe=1024
p63:~#

Justin.