[Cluster-devel] [PATCH 2/2] gfs2: Extended attribute readahead optimization

[Bob Peterson <rpeterso@redhat.com>]

----- Original Message -----
> On Thu, Nov 12, 2015 at 9:33 PM, Steven Whitehouse <swhiteho@redhat.com>
> wrote:
> > That looks good to me, and I assume that it should be faster too?
> 
> I did some tests with a directory tree with 3439 directories and 51556
> files in it.
> 
> In that tree, 47313 or 86% of the 54995 files and directories ended up
> with readahead enabled, while 7682 didn't.
> 
> On a slow SATA magnetic disc, I compared the time required for running
> "find", then "find | xargs stat", then "find | xargs getfattr". I
> booted with selinux=0 for these measurements, so "find" and "find |
> xargs stat" didn't use the xattrs.
> 
> The results are attached as a spreadsheet. They show that xattr
> readahead can save quite some time (here, about -75%). The optimized
> version of xattr readahead is about 3% faster than the simple version
> in this test, so I'll leave it up to you whether that's worth it for
> you.
> 
> It makes no difference whether the scheduler is "noop" or "deadline"
> here; the "noop" scheduler still seems to merge adjacent I/O requests
> (which makes sense).
> 
> Andreas
> 
Hi,

Thanks. Both patches are now applied to the for-next branch of the linux-gfs2 tree:
https://git.kernel.org/cgit/linux/kernel/git/gfs2/linux-gfs2.git/commit/fs/gfs2?h=for-next&id=c8d577038449a718ad0027d1790b6ef4441715d4
https://git.kernel.org/cgit/linux/kernel/git/gfs2/linux-gfs2.git/commit/fs/gfs2?h=for-next&id=843396ad9886458bddbc7d07137b2975876b029e

Regards,

Bob Peterson
Red Hat File Systems