Patch: Tune "dir" a bit

[Volker Lendecke]

On Mon, Mar 25, 2013 at 12:16:06PM -0400, Scott Lovenberg wrote:
> On Mon, Mar 25, 2013 at 12:10 PM, Jeremy Allison <jra at samba.org> wrote:
> > 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 :-).
> 
> Ooh! I've never used cachegrind.  Sounds like a good excuse to play
> with something new.  :)
> 
> I'll give it a test run and post my results.

Hmm. I can't reproduce this locally.

This is 3.5.21-GIT-26a043a:

real    0m28.121s
user    0m9.921s
sys     0m10.481s

and this is current master with the tuning patch:

real    0m27.588s
user    0m9.021s
sys     0m10.857s

So they are pretty much similar. Maybe you have wildly
different compiler options?

Volker

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