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Peter Zaitsev <peter@mysql.com> wrote: > > On Thu, 2004-05-06 at 01:43, Andrew Morton wrote: > > > > > One thing I note about this test is that it generates a huge number of > > inode writes. atime updates from the reads and mtime updates from the > > writes. Suppressing them doesn't actually make a lot of performance > > difference, but that is with writeback caching enabled. I expect that with > > a writethrough cache these will really hurt. > > Perhaps. By the way is there a way to disable update time modification > as well ? No, there is not. > It would make quite a good sense for partition used for > Database needs - you do not need last modification time in most cases. First up, one needs to remove the inode_update_time() call from generic_file_aio_write_nolock() and run the tests. If this (and noatime) indeed makes a significant difference (probably on writethrough-caching disks) then yup, we should do something. `nomtime' would be simple enough. But another option would be to arrange for a/m/ctime dirtiness to not cause an inode writeout in fsync(). Instead, only sync the a/m/ctime-dirty inodes via sync, umount and pdflush. That way, the inodes get written every thirty seconds rather than once per second. It's probably not standards-compliant, but shoot me. Who cares if the mtimes come up 30 seconds out of date after a system crash? `nomtime' would be simpler and safer to implement, but not as nice. But we need those numbers first. I'll take a look. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ | ||||||||||||
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