Hi Anton, On Thu, Oct 15, 2009 at 09:08:54PM +1100, Anton Blanchard wrote: > > Hi Nick, > > > Several people have been interested to test my vfs patches, so rather > > than resend patches I have uploaded a rollup against Linus's current > > head. > > > > ftp://ftp.kernel.org/pub/linux/kernel/people/npiggin/patches/fs-scale/ > > > > I have used ext2,ext3,autofs4,nfs as well as in-memory filesystems > > OK (although this doesn't mean there are no bugs!). Otherwise, if your > > filesystem compiles, then there is a reasonable chance of it working, > > or ask me and I can try updating it for the new locking. > > > > I would be interested in seeing any numbers people might come up with, > > including single-threaded performance. > > Thanks for doing a rollup patch, it made it easy to test. I gave it a spin on > a 64 core (128 thread) POWER5+ box. I started simple by looking at open/close > performance, eg: > > void testcase(void) > { > char tmpfile[] = "/tmp/testfile.XXXXXX"; > > mkstemp(tmpfile); > > while (1) { > int fd = open(tmpfile, O_RDWR); > close(fd); > } > } > > At first the results were 10x slower. I took a look and it appears the > MNT_MOUNTED flag is getting cleared by a remount (I'm testing on the root > filesystem). This fixed it: Oh dear, thanks for that. That bugfix is needed for the patchset I just sent to be merged. > --- fs/namespace.c~ 2009-10-15 04:34:02.000000000 -0500 > +++ fs/namespace.c 2009-10-15 04:35:00.000000000 -0500 > @@ -1711,7 +1711,8 @@ static int do_remount(struct path *path, > else > err = do_remount_sb(sb, flags, data, 0); > if (!err) > - path->mnt->mnt_flags = mnt_flags; > + path->mnt->mnt_flags = mnt_flags | > + (path->mnt->mnt_flags & MNT_MOUNTED); > up_write(&sb->s_umount); > if (!err) { > security_sb_post_remount(path->mnt, flags, data); > > Attached is a before and after graph. Single thread performance is 20% > faster, and we go from hitting a wall at 2 cores to scaling all the way > to 64 cores. Nice work!!! Nice looking graph, thanks! Did you use the rcu patch there as well? (my open-close testing chokes RCU but your system might be managing to keep outstanding callbacks below the threshold) -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
