CPU Affinity Made Easy

nice post karan but images not working

eh? i can see all the images right in front of me...... whts up?

Repped!
This will help Dual Core users a lot!

Thought with the /PMTimer it doesnt matter...

Im still gonna use to set Priority...

thnx man........

I did this, here is my Target:

C:\WINDOWS\system32\cmd.exe /C start /AFFINITY 1 D:\Games\Oblivion\OblivionLauncher.exe

When I click the game icon nothing happens, all it looks like it's trying to do is just lauch the cmd prompt.

What am I doing wrong?

THANKS

I'm having the exact same problem for Warcraft III. I've tried without quotes around the game location, with quotes, with quotes around the location and the start commands, everything. All of them have the exact same problem, which you described.

It might be related to the fact that I do indeed have a dual core processor, but when I go into a cmd prompt and type "start /?", there's one option missing, the /AFFINITY option; it has all of the others that are shown in the screenshot of the cmd prompt in the original post.

Does anyone have any ideas why /AFFINITY isn't showing up in the list of possible start parameters, and why we're having the problem of the cmd window coming up but then not launching the program?

use this much easier
http://www.geocities.com/edgemeal_so.../LnS/Index.htm

nice guide there karan although u people can try this as well

Force Core

short addition to this guide. the numeric parameter after /affinity is a hexadecimal parameter like stated earlier, but it's not as straightforward as 1,2,3,4,5...

if you know how ownership modes (chmod) codes work then this will be a breeze:

1st core = 1
2nd core = 2
3rd core = 4
4th core = 8
5th core = H ( hexadecimal 16 )
6th core = 1H ( hexadecimal 32 )

now if you want something to run on just one core, you pick the right number like this, just multiply by 2 until you get to the core you want.

if you want something to run on two cores, you ADD their values:

1st and 2nd core = 1 + 2 = 3
1st and 3rd core = 1 + 4 = 5
2nd and 3rd core = 2 + 4 = 6
2nd and 4th core = 2 + 8 = 10

Same thing if you want more than two cores, just add each core numerical value up and use the sum as the /affinity parameter

Tested and retested on a 8 core system.

HTH

ok, sorry.. im tired, correction:

1st core = 1
2nd core = 2
3rd core = 4
4th core = 8
5th core = 10 ( hexadecimal 16 )
6th core = 20 ( hexadecimal 32 )

I had been banging my head against a wall with this for some time. I finally got it mostly figured out, here are some tips to make your life easier.

Firstly, if you are having the issue where it looks like it's just attempting to open a cmd prompt. It might be because your either not pointing to the working directory or your working directory requires "quotes".

To get around this do a search on your system for "cmd". It should be in C:\Windows\System32. Copy the cmd.exe to the directory with the executable you want to run in affinity or priority. You can do it from the GUI or from a command line. In this example I'll use virtual pc 2007.

copy c:\windows\system32\cmd.exe c:\program files\microsoft virtual pc\

Second, now that a copy of cmd.exe is in your working directory with your executable, right click on your newly added cmd.exe and create a shotcut.
You can now move the shortcut to wherever you want (Desktop, Start Menu, wherever.)

Third, if you fire up your shortcut now you'll notice that it automatically starts you in the directory where your copied cmd is sitting. It would show up like this. (Note: this test is being done on Vista Ultimate 64-bit for reference)

Microsoft Windows [Version 6.0.6000]
Copyright (c) 2006 Microsoft Corporation. All rights reserved.

C:\Program Files\Microsoft Virtual PC>

Third, now right click on your shortcut and go to properties. Where you see "Target" you should see something like this.

"C:\Program Files\Microsoft Virtual PC\cmd.exe"

This is where you add your start command, throwing the /c tells it to execute a command and then terminate. Then you can add your priority switches and affinity switches with the Start command. Add this right into your shortcut target Like so.

"C:\Program Files\Microsoft Virtual PC\cmd.exe" /c start /realtime /affinity 3 vpc.exe

The /realtime is the priority I chose for my program, by choosing affinity 3 I'm telling the program to only use processors 0 and 1. This example is being done on a 4 processor system, I would not recommend using /realtime unless you have remaining processors to handle the load, If this system only had 2 processors I would not exceed /high for my priority.

(Note, the virtual pc 2007 executable is normally named "Virtual PC.exe" I have renamed it "vpc.exe" to avoid having to use "" quotes which causes the command to fail. As best I can tell I think it's because windows doesn't like playing with 2 sets of "" quotes in the same command, just my guess here.)

Here comes a complicated part, choosing the value for affinity, notice below there are some letters, thats not a typo, the /affinity switch is looking for a Hexadecimal value. This should be fairly accurate, math was never my best subject though.

1 does processor 0
2 does processor 1
3 does processors 0 and 1
4 does processor 2
5 does processors 0 and 2
6 does processors 1 and 2
7 does processors 0, 1, and 2
8 does processor 3
9 does processor 0 and 3
D does processor 0, 2, and 3
F does processors 0, 1, 2, and 3


This Microsoft technet chart may help.
Microsoft Corporation

Also note, some programs are setup to force a specific affinity, I have run into some programs using this technique that will not take affinity settings past a certain number of CPU's. So for example, if you set /affinity F and the application is still not using all 4 cpus, this does not necessarily mean you did the command wrong, the program may just be enforcing it's affinity.

Now that you have your shortcut setup you can change the name, the icon, if your using Vista you can right click on the shortcut, change icon, and browse to the original .exe to use the same icon file.

This was driving me nuts for some time I hope this helps somebody out!

manually setting affinity was needed in the days of the dual cores.
C2Ds, quads and modern AM2s don't need that due to recent optimizations and drivers.
I was also intrigued by affinity settings when I bought my am2. But my queries were answered by some old timers at amd forums.
Your boot.ini wud have the switche /usepmtimer if you have the optimal dual core drivers.

You really don't know what you are talking about, do you? Do you even know why there is a need (ever) for CPU affinity? Sorry for being argumentative, but multicore systems happen to be my bread and butter...
I am willing to accept that the Operating system can handle these issues, but not that the processors can (the current lot can't at any rate).
Certainly, perhaps with the newer drivers you can get around the bugs that sometimes occur on running some single threaded programs on multicore computers (Thief 3 comes to mind..), but there are many other issues involved. I do think however, that setting an affinity is at least conceptually a bad idea, but at least with Linux, it may some times be required (I haven't performed the same tests on Windows)

I do understand every word what I am talking about, and frankly can churn out a better automated script to do this on a per PID basis on Windows.
You can do on the fly affinity settings as soon as a particular application class/process is discovered, but you'd need a script in the background to run continuously to achieve that.

I am on Windows. Some of you guys think you are the Crème de la Crème, with the right to preassume right.
btw, i don't need to show my credentials to assert that I am smarter (or pathetic).

On Topic:
Affinity setting may or may not be beneficial for those on quaddies or greater but its absolutely supefluous if you do it on a dual core with current drivers for windows.

Sorry for being argumentative