Patch: Tune "dir" a bit

[Scott Lovenberg]

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.

-- 
Peace and Blessings,
-Scott.