On Thu, 2008-08-14 at 21:10 -0400, Chris Mason wrote: > On Thu, 2008-08-14 at 19:44 -0400, Theodore Tso wrote: > > > I spent a bunch of time hammering on different ways to fix this without > > > increasing nr_requests, and it was a mixture of needing better tuning in > > > btrfs and needing to init mapping->writeback_index on inode allocation. > > > > > > So, today's numbers for creating 30 kernel trees in sequence: > > > > > > Btrfs defaults 57.41 MB/s > > > Btrfs dup no csum 74.59 MB/s > > > Btrfs no duplication 76.83 MB/s > > > Btrfs no dup no csum no inline 76.85 MB/s > > > > What sort of script are you using? Basically something like this? > > > > for i in `seq 1 30` do > > mkdir $i; cd $i > > tar xjf /usr/src/linux-2.6.28.tar.bz2 > > cd .. > > done > > Similar. I used compilebench -i 30 -r 0, which means create 30 initial > kernel trees and then do nothing. compilebench simulates compiles by > writing to the FS files of the same size that you would get by creating > kernel trees or compiling them. > > The idea is to get all of the IO without needing to keep 2.6.28.tar.bz2 > in cache or the compiler using up CPU. > > http://www.oracle.com/~mason/compilebench Whoops the link above is wrong, try: http://oss.oracle.com/~mason/compilebench It is worth noting that the end throughput doesn't matter quite as much as the writeback pattern. Ext4 is pretty solid on this test, with very consistent results. -chris -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
