[PATCH] fix some performance gaps in Xace

[Arjan van de Ven]

On Mon, 05 Nov 2007 11:22:29 -0500
Eamon Walsh <ewalsh at tycho.nsa.gov> wrote:

> Arjan van de Ven wrote:
> >>From 50d6941ab3af3297212fbcc20231bcaf0c8c6463 Mon Sep 17 00:00:00
> >>2001
> > From: root <root at benny.jf.intel.com>
> > Date: Tue, 30 Oct 2007 23:43:24 +0100
> > Subject: [PATCH] fix some performance gaps in Xace
> > 
> > The XaceHook function is used in several hotpaths.
> > The problem with it (performance wise) is twofold:
> >  * The XaceHook function has a big switch() statement for the hook
> > number in it
> >  * The XaceHook function uses varargs to reassemble the final
> > dispatch arguments again
> > 
> > Both are expensive operations... for something that is known at
> > compile time
> > 
> > This patch turns the hotpath XaceHook call into a direct call to
> > avoid the switch and varargs; this gives me over 10% performance
> > gain on the x11perf benchmark.
> 
> Thanks for the patch.  Could I get a copy of your numbers, I have
> some x11perf results from some point that don't show this big of a
> hit.
> 

sure; first set of numbers is for with the optimized patch, second set
of numbers is without the patch 


x11perf - X11 performance program, version 1.5
The X.Org Foundation server version 10400001 on :0.0
from xxxx.intel.com
Sat Nov  3 23:22:55 2007

Sync time adjustment is 0.0522 msecs.

90000000 reps @   0.0002 msec (5700000.0/sec): X protocol NoOperation
90000000 reps @   0.0002 msec (5700000.0/sec): X protocol NoOperation
90000000 reps @   0.0002 msec (5700000.0/sec): X protocol NoOperation
90000000 reps @   0.0002 msec (5700000.0/sec): X protocol NoOperation
90000000 reps @   0.0002 msec (5700000.0/sec): X protocol NoOperation
450000000 trep @   0.0002 msec (5700000.0/sec): X protocol NoOperation


x11perf - X11 performance program, version 1.5
The X.Org Foundation server version 10400001 on :0.0
from xxxx.intel.com
Sat Nov  3 23:19:32 2007

Sync time adjustment is 0.0522 msecs.

80000000 reps @   0.0002 msec (5200000.0/sec): X protocol NoOperation
80000000 reps @   0.0002 msec (5210000.0/sec): X protocol NoOperation
80000000 reps @   0.0002 msec (5210000.0/sec): X protocol NoOperation
80000000 reps @   0.0002 msec (5210000.0/sec): X protocol NoOperation
80000000 reps @   0.0002 msec (5210000.0/sec): X protocol NoOperation
400000000 trep @   0.0002 msec (5210000.0/sec): X protocol NoOperation