On Wed, Jun 12, 2013 at 09:17:43AM -0500, Ben Myers wrote: > Hey Dave, > > On Wed, Jun 12, 2013 at 08:22:20PM +1000, Dave Chinner wrote: > > Thoughts, comments, flames? > > Do you have any performance numbers recorded for the block queue plugging for > bulkstat and the new inode create transaction? The new inode create transaction doesn't change performance on my test rigs. It significantly reduces log traffic under heavey create workloads (up to 50% lower). However, given the reduction is only from 60MB/s down to 30MB/s at 110,000 inodes/s being created, log performance is not a performance limiting factor on any of my test rigs. That said, the reason for the change is not so much for immediate improvements in inode create performance. Want to allocate a stripe width of inodes at a time? The new transaction can do that atomically.... Ordered buffers allow all sorts of interesting things to be done - do you want to add an ext3/4 style data=ordered mode? We can do that with ordered buffers. Synchronous writes of remote attribute data? Ordered buffers can be used to make that async and driven by AIL flushing. Want to use intent-based logging for operations rather than physical object logging? Ordered log items and metadata stamped with the last modification LSN are necessary, and with this icreate transaction we end up with all the pieces we need to do this.... And for bulkstat, performance differences were documented in this email where I found the problem: http://oss.sgi.com/pipermail/xfs/2013-June/026922.html It took a mulithreaded bulkstat from being IO bound at 450,000 inodes/s @ 220MB/s and 27,000 IOPS to being CPU bound at 750,000 inodes/s @ 350MB/s and 14000 IOPS. And given that it increased IO sizes from 8k to 16k for 256 byte inodes and to 32k for 512 byte inodes, that is going to increase performance on any busy filesystem simply through the fact that bulkstat IOPS overhead goes down by a factor of 2/4/8/16 depending on inode size..... Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
