Automatically setting cpu affinity for SAC

[Angie]

This is a new thread based on a discussion here http://www.sawstudiouser.com/forums/...3&postcount=11

As mentioned in the above thread, changing the affinity for SAC to run on only one CPU can help with performance on some systems. In my case, it eliminated dropped buffers when using a remote. Yes, you can use the /onecpu switch at boot. But some times you don't want to eliminate both CPUs. Or you can use the single cpu menu setting in SAC itself, but that didn't work for me. I needed to set to a specific CPU. Setting affinity manually to the second CPU was the answer. But in a volunteer situation, having it done automatically is best.

Enter a utility program called Imagecfg. This is a microsoft utility that was available in the 2000 server toolkit and may already be in the windows directory for Vista and up, but is not in XP. You can download it here. http://www2.robpol86.com/guides/ImageCFG/
This page gives instructions on it's use. The only thing you really need to know is the command line switch for setting the process affinity (-a) and the CPU value.

The information on the web on Imagecfg.exe is slightly confusing. There are discussions on using batch files for the program you want to change, etc. But none of that is necessary. Run once, Imagecfg PERMANENTLY changes the hex image of the effected program itself. Because of the nature of SAC, you can run the program once on any computer and simply copy the effected SAC.exe to any machine that needs to run SAC on a single, specific CPU.

So, here's what you do. Put imagecfg.exe in the SAC directory. (You can actually run it from anywhere, even a flashdrive.) From a command prompt, use this string.
C:\SAC\imagecfg -a 0X02 "C:\SAC\SAC.exe"
SAC will now run on the second CPU EVERY TIME it loads. (Change the "2" for other CPUs)

You know it worked if the date on SAC.exe has changed to that days date. Test further by looking at the affinity for SAC in the task manager.

Hope this is helpful.

[Trackzilla]

Very nice info Angie

[RBIngraham]

+1, thank you for posting this info

[Bruce Callaway]

FWIW, I use this for setting affinity for SAC & SAW on startup and as Angie says, it works very well.

[Paul Henry]

I've used Imagecfg in the past for older programs that didn't speak multiprocessor. It always did the job well.

[Donnie Frank]

Thanx, Angie. Because my present system is so solid, I have been leery of upgrading my older socket LGA-775 for this very reason. Thanx for this information!

[Carey Langille]

OK, so, this sounds very cool, But im not sure i completely understand.. SAW/SAC will run now on your second CPU, will then other things run on CPU one? How about VST's do they stay on CPU 2 with SAW or do they use 2 or 1 or whatever? How do they Interact with each other? Inquiring Minds WANT TO KNOW! Has Bob explored this in the past?

[RobertV]

OK, so, this sounds very cool, But im not sure i completely understand.. SAW/SAC will run now on your second CPU, will then other things run on CPU one? How about VST's do they stay on CPU 2 with SAW or do they use 2 or 1 or whatever? How do they Interact with each other? Inquiring Minds WANT TO KNOW! Has Bob explored this in the past?

Carey;
Please have a read through this,
http://www.sawstudiouser.com/forums/...light=affinity

Re; VSTs and Affinity etc..

Cheers...Robert V

[tomasino]

Dittos.. Thanks Angie!

In the past, toyed with the /ONECPU and internal app. settings, but never noticed any diff.. n' don't know where I left it.

Gonna implement this on the studio rig just to set and forget it.

[tomasino]

Dittos.. Thanks Angie!

In the past, toyed with the /ONECPU and internal app. settings, but never noticed any diff.. n' don't know where I left it.

Gonna implement this on the studio rig just to set and forget it.

Implemented this last weekend.
Started on the ground floor by disabling hyperthreading in the BIOS. (was still enabled.. who knew! )
Ran imagecfg on SAC.exe n' set its' affinity to the 2nd core (i3 2 core 3.4 Gigawatts )
In Sawstudio set "Force Single CPU".

So, should have:

• Sawstudio on core Zero
• SAC on core One

Then, experienced a little weirdness in Sawstudio on BuildMix.. but nothing a reboot didn't clear up.
Have had some stuttered start boot ups.


There should be no problem for the Win7 OS with disabling hyperthreading in the BIOS right?
Pretty sure it was ON when the OS was installed.
OS is installed on an SSD drive.

Otherwise seems to be OK.
Not noticing any diff in the MultiTrack/SAC load.