dual core affinity performace gains

[RFC Rudel]

I finish my research on CPU affinity performance for games on dual core or dual CPU systems.

I use windows w2k3 enterprise because is the only available OS that can run the windows resource manager. (http://www.microsoft.com/windowsser...loads/wsrm.mspx)

To check the process affinityand CPU usage I use sysinternals process explorer

(http://www.sysinternals.com/Utiliti...ssExplorer.html).

The windows resource manager allows you to make affinity policies for process and services.

EJ: you configure WRM to run all the OS on CPU0 and the .exe of your games or other single treaded apps on CPU1.

The WRM works as a service so if you have the service on manual your OS starts like the average Joe dual system and all of your games and app run on both cores or wherever the OS tread scheduler thinks they should run.

The WRM do not allow you to manage the OS process, but a quick registry edit cleaning the System Exclusion List you could make one of your cores totally empty and ready for your CPU hungry single treaded apps/games.

I chose to make CPU1 free because CPU0 is the default for several things.

Performance Gains

I use PI calculations, Sandra, 3dmark 2003&2005, CPU only benchmarks etc.

On PI calculations or any other single treaded CPU benchmark if you make it run with the WRM properly configured you get 5% or less gains in performance, but your OS stays totally responsive because the tread of the bench app do not interfere with all the OS and user process. (the score of single treaded is half the score of a dual cpu capable app.)

3dmark give some 5% or less.

In games is a totally different story.

If the game is pretty much VGA limited (like BF2) your gains will be on parts where the CPU became the limit, I get more max FPS number but my average FPS gains in BF2 are 8/10% at the most.

In BF2 I pass from a max 80FPS to 92FPS, as I said before on games that are seriously VGA limited the gains are limited but they exist.

On HL2 my x800xl is not too much of a bottleneck so in normal mode (no affinity optimizations) I put Dr freeman steady at 150FPS and when I start the WRM and the HL2 run alone on CPU1 my FPS jump to 182!!!

I use a creative X-FI so in theory the board unloads my CPU from audio calculations; I think that people with onboard audio should get better results.

IRQ

I use a resource kit utility to redirect all IRQ to CPU0 but I was unable to get a tangible performance gain.

Application Needed

I change the WRM .msi to run on XP but it fails to install the WRM service.

The only way to manage OS process affinity in XP is using sysinternals process explorer, but is not automatic.

I think that a application is needed because it is a pain to set up all the affinities by hand not to mention that there is a IRQ and tread process priority performace gains not deeply explored.

I found that NCR SMP Utilization Manager very awkward but has some nice features.

http://www.ncr.com/support/pcfiles/...LS/SMPUT200.EXE

So far the WRM is the best to manage process affinity.

WE NEED SOMEONE TO MAKE AND APP LIKE THE WRM FOR XP.

We need a soft that automaticaly unload one core and make your game run alone en the other core or cpu no matter if is an xp or w2k3.

please if you want to recreate this feel free to ask.

My machine:

LANPARTY UT nF4 SLI-DR

AMD 3800 Dual core@2.55Ghz

2x1G Ram TCCC (OCZ ASAP)

ATI X800XL

Creative X-FI EM

3x sata2 hitachi 80GB Raid0

1 WD 80GB

Nec DVD-R

Samsung DVD-CDR combo

Thernaltake Armour

Thermaltake 680W PSU

Aerocool Coolpanel (Front Panel)

Windows 2003 enterprise

Edited October 19, 2005 by RFC Rudel

[JuMz]

I know this thread is really old but I see this as having some important implications given all the new dual core cpu's that are out...