On 2012-02-01, at 1:35 AM, Kazuya Mio wrote: > 2012/01/31 5:36, Andreas Dilger wrote: >> Can you please run this same measurement on ext4 formatted and running >> with the default options? I'd like to know if this is still a problem >> in ext4 or not. > > I performed the same measurement on ext4 with the default options. Kazuya, thank you for running this test. I'm unfortunately confused by the result. > Here is its result: > > filesystem time(sec) call extX_mark_inode_dirty(times) > --- > ext3 220.5 50,338,104 > ext3 (patched) 196.3 25,169,658 > ext4 (*1) 190.3 28,465,799 > ext4 (*2) 201.5 27,963,473 > ext4 (default) 223.3 14,026,118 > > *1 disable ext4-specific options (delalloc, extent, and so on) > *2 disable only delalloc option This shows that ext4 with extents+delalloc is _slower_ than ext3, which is very strange. In other similar tests of write performance (see http://downloads.linux.hp.com/~enw/ext4/3.2/large_file_creates.html, showing multi-threaded 1GB file writes) ext4 is much faster than ext3. Looking at your original email, is ext4 being tested on a RHEL 5.5 (2.6.18) kernel, or a more recent kernel? It would be more useful to run this on a more modern kernel, since the ext4 code backported to RHEL5 was barely supporting delalloc at all, if I remember correctly. The good news is that the number of extN_mark_inode_dirty() calls is far lower in ext4 than in ext3, though this doesn't seem to be the primary factor in the performance in this case. Cheers, Andreas -- 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
