On Fri, Aug 13, 2010 at 08:29:07AM -0400, Christoph Hellwig wrote: > On Fri, Aug 13, 2010 at 12:35:44PM +0200, Michael Monnerie wrote: > > On Freitag, 13. August 2010 Stan Hoeppner wrote: > > > Some benchmark results maybe worth a look: > > > http://btrfs.boxacle.net/repository/raid/2.6.35-rc5/2.6.35-rc5/ > > > > Thanks - it would have been great to see xfs with delaylog in that > > comparison, but the graphs are very very nice. > > > > XFS seems performing better the more threads there are, just in "large > > file random reads" it's the slowest - why this? > > Any idea who is doing these runs? IIRC the tests are run by someone from IBM, but I cannot remember who it is. > Once we figure out what that large > file random reads loads is I'm sure we could fix it soon. >From http://btrfs.boxacle.net/: Random Reads (raid, single-disk) Start with 1024 files. 100 MB files on the raid system. 35 MB files on the single-disk system. Each thread reads a fixed amount of data from a random location in one file using 4 kB reads. 5 MB reads on the raid system. 1 MB reads on the single-disk system. So it's not a small random read workload (100GB data set), so the files on XFS are probably more spread out over multiple AGs and hence further apart than other filesystems. Hence a greater average seek distance, hence it slower throughput.... > And asking > him/her to add -o delaylog would also be good. Yes, that would be an interesting comparison... Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
