Messages in this thread | | | Date | Fri, 30 Jul 2010 23:01:36 +0200 | From | Kay Diederichs <> | Subject | Re: ext4 performance regression 2.6.27-stable versus 2.6.32 and later |
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Am 30.07.2010 04:20, schrieb Ted Ts'o: > On Wed, Jul 28, 2010 at 09:51:48PM +0200, Kay Diederichs wrote: >> >> When looking at the I/O statistics while the benchmark is running, we >> see very choppy patterns for 2.6.32, but quite smooth stats for >> 2.6.27-stable. > > Could you try to do two things for me? Using (preferably from a > recent e2fsprogs, such as 1.41.11 or 12) run filefrag -v on the files > created from your 2.6.27 run and your 2.6.32 run? > > Secondly can capture blktrace results from 2.6.27 and 2.6.32? That > would be very helpful to understand what might be going on. > > Either would be helpful; both would be greatly appreciated. > > Thanks, > > - Ted
Ted,
a typical example of filefrag -v output for 2.6.27.48 is
Filesystem type is: ef53 File size of /mnt/md5/scratch/nfs-test/tmp/xds/frames/h2g28_1_00000.cbf is 6229688 (1521 blocks, blocksize 4096) ext logical physical expected length flags 0 0 796160000 1024 1 1024 826381312 796161023 497 eof
(99 out of 100 files have 2 extents)
whereas for 2.6.32.16 the result is typically Filesystem type is: ef53 File size of /mnt/md5/scratch/nfs-test/tmp/xds/frames/h2g28_1_00000.cbf is 6229688 (1521 blocks, blocksize 4096) ext logical physical expected length flags 0 0 826376200 1521 eof /mnt/md5/scratch/nfs-test/tmp/xds/frames/h2g28_1_00000.cbf: 1 extent found
(99 out of 100 files have 1 extent)
We'll try the blktrace ASAP and report back.
thanks,
Kay
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