On Fri, 30 May 2008 17:50:43 +0200 Valerie Clement <valerie.clement@xxxxxxxx> wrote: > Hi all, > > Since a couple of weeks, I did batches of tests to have some > performance numbers for the new ext4 features like uninit_groups, > flex_bg or journal_checksum on a 5TB filesystem. > I tried to test allmost all combinations of mkfs and mount options, > but I put only a subset of them in the result tables, the most > significant for me. > > I had started to do these tests on a kernel 2.6.26-rc1, but I'd got > several hangs and crashes occuring randomly outside ext4, sometimes > in the slab code or in the scsi driver eg., and which were not > reproductible. Since 2.6.26-rc2, no crash or hang occur with ext4 on > my system. > > The first results and the test description are available here: > http://www.bullopensource.org/ext4/20080530/ffsb-write-2.6.26-rc2.html > http://www.bullopensource.org/ext4/20080530/ffsb-readwrite-2.6.26-rc2.html > > I will complete them in the next days. > > In the first batch of tests, I compare the I/O throughput to create > 1-GB files on disk in different configurations. The CPU usage is also > given to show mainly how the delayed allocation feature reduces it. > The average number of extents per file shows the impact of the > multiblock allocator and the flex_bg grouping on the file > fragmentation. At last, the fsck time shows how the uninit_groups > feature reduces the e2fsck duration. > > In the second batch of tests, the results show improvements in > transactions -per-second throughput when doing small files writes, > reads and creates when using the flex_bg grouping. > The same ffsb test on an XFS filesystem hangs, I will try to have > traces. > > If you are interested in other tests, please let me know. How about adding the following in "[filesystem0]" to age the filesystem: agefs=1 [threadgroup0] num_threads=10 write_size=40960 write_blocksize=4096 create_weight=10 append_weight=10 delete_weight=1 [end0] desired_util=0.80 This will age the filesystem until it reaches 80% utilization before starting the benchmark. Since a 5TB disk will take a while to age, I suggest trying this on just a few runs. > > Valérie > -JRS -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
