Patch: Tune "dir" a bit

Jeremy Allison jra at samba.org
Mon Mar 25 10:10:16 MDT 2013


On Sat, Mar 23, 2013 at 12:07:40PM -0400, Scott Lovenberg wrote:
> On Sat, Mar 23, 2013 at 11:55 AM, Scott Lovenberg
> <scott.lovenberg at gmail.com> wrote:
> > On Fri, Mar 22, 2013 at 1:20 PM, Jeremy Allison <jra at samba.org> wrote:
> >> On Fri, Mar 22, 2013 at 02:37:31PM +0100, Volker Lendecke wrote:
> >>> Hi!
> >>>
> >>> Attached find a patch that makes trans2_findfirst take 10%
> >>> less user-space CPU. If someone has the time, can you try to
> >>> verify this improvement and push?
> >>
> >> Indeed this is a significant improvement - I'll push to
> >> autobuild and get a bug logged for 4.0.x and 3.6.x to
> >> get this change into production releases asap.
> >>
> >> Jeremy.
> >
> > FWIW, I confirmed this on a VM because I was really curious.  The
> > difference is dramatic when IO is more costly (ie: on a VM running on
> > an old P4).  This is the same test that Volker ran:
> > ---------------------------------------------------------------------------------------
> > [root at primary sambaTest]# time /usr/sbin/smbd -d0 -i
> > smbd version 3.5.10-125.el6 started.
> >
> > real    13m11.306s
> > user    0m45.899s
> > sys     4m0.341s
> >
> >
> > [root at primary sambaTest]# time /opt/sambaTest/sbin/smbd -d0 -i
> > smbd version 4.1.0pre1-GIT-9624ca4 started.
> >
> > real    13m51.811s
> > user    1m12.406s
> > sys     4m25.588s
> > ---------------------------------------------------------------------------------------
> >
> > Volker, well done!
> > --
> > Peace and Blessings,
> > -Scott.
> 
> 
> I feel really stupid.  I interpreted my results backwards.  Why in the
> world is 3.5 doing so much better than 4.1?
> Thanks to Ira for pointing this out to me. :P

So this is an ideal test case for cachegrind :-). Nice isolated
test, one process serving... I'd love to see comparitive cachegrind
results (hint, hint :-).


More information about the samba-technical mailing list