Forged Alliance Forever

Re: Processor Affinity and single core game designs

2013-01-30T10:23:31+02:00

I've run a simple test.

Fa forever on perftest map.

FA took almost 100% of my first core. then others core took some more % (I presume windows was moving process on other core to let FA take more).

To confirm that, I've run another expensive software :

Capture.PNG

As you can see, it took the 3rd core, while FA process still take most of the first one.

So it's exactly what I'm saying : as FA take most of a core, affinity will just move it around, but it will be maxed out whatever you do.
Windows 7, by default, is averaging the charge over the other cores correctly.

You should really enable HT if you can. There is almost no drawbacks, but it allow windows to be smarter with process affinity.
It's like a hanoi game :
images.jpeg
If it doesn't have enough place to move things around, it can't. The more it has, the more efficient it will be.

If you are worried about losing performance with a single threaded app, don't worry you won't :
Even it show 25% CPU for FA, if a thread is maxed out with HT, it will take the full power of a core.

Statistics: Posted by Ze_PilOt — 30 Jan 2013, 10:23

Re: Processor Affinity and single core game designs

2013-01-28T14:28:27+02:00

Maybe it's the compatibility mode. Or maybe it put other process on core 1 ? How many cores do you have ?

I can run some more test at home with FA, here at work with a 32-cores machine, it's not really a common configuration

Statistics: Posted by Ze_PilOt — 28 Jan 2013, 14:28

Re: Processor Affinity and single core game designs

2013-01-28T14:37:21+02:00

On my computer that does not happen. When running FA, core0 is 100% all the time. Core maximizer changes that. One important point that may impact this is that I run FA in Windows XP SP3 compatibility mode.

One survey you should do is: How many players use laptops and WIFI? You should give those players a special Avatar ^^.

You may also consider a Technical forum so debates like this don't invite the flames of the General forum.

My CPU is a i5 2500K. Note: no HT (Maybe Microcrap made a back room deal with Hitel to disable load balancing when the customer doesn't buy i7)

I have used Core Maximizer from Socket 939 Athlon 2 core. The difference was night and day back then. The behavior I have seen as far as affinity has been the same up until today. I have always run in compatibility mode.

Statistics: Posted by ThinkTank — 28 Jan 2013, 13:40

Re: Processor Affinity and single core game designs

2013-01-28T13:34:08+02:00

ThinkTank wrote:
If you believe Windows 7 does this, show me the instance when FA.exe is the only process running on core0.

My example is actually doing that. Except that 7 is moving it around each time it balance the load of other apps.

Statistics: Posted by Ze_PilOt — 28 Jan 2013, 13:34

Re: Processor Affinity and single core game designs

2013-01-28T13:30:40+02:00

If you believe Windows 7 does this, show me the instance when FA.exe is the only process running on core0.

Statistics: Posted by ThinkTank — 28 Jan 2013, 13:30

Re: Processor Affinity and single core game designs

2013-01-28T13:28:58+02:00

ThinkTank wrote:
It wont move them to core 0 if it is 100%. So it has less options to balance. You never want to run a core at 100% if you have multiple cores.

What you really don't understand is that you don't have a choice. FA take as much as CPU as it can.

It's like the app I'm running in my exemple. I don't have the choice to run it at less than 100% of a core.

Actually, setting core affinity on that app will make thing worst, as it won't be able to balance the cores efficiently anymore. Actually some user has reported that Core Maximizer made FA run SLOWER, so I wouldn't be surprised that we are in that case on some CPUs.

Statistics: Posted by Ze_PilOt — 28 Jan 2013, 13:28

Re: Processor Affinity and single core game designs

2013-01-28T13:28:03+02:00

ThinkTank wrote:
FA is not the only process using the core thus it runs at 100%. That is bad. I have made no claims about how processes are allocated to each core and I think your example is over simplified and invalid.

If load balancing does no harm you should use it for the benefits I have described above.

What you don't understand is that seven already does a great job at load balancing.
If one app need 100% of one core, it will reserve one core for it, unlike XP.

Statistics: Posted by Ze_PilOt — 28 Jan 2013, 13:28

Re: Processor Affinity and single core game designs

2013-01-28T13:29:18+02:00

It wont move them to core 0 if it is 100%. So it has less options to balance. You never want to run a core at 100% if you have multiple cores. To be clear, when I run Setons it goes %100 on core0 late game.

Statistics: Posted by ThinkTank — 28 Jan 2013, 13:26

Re: Processor Affinity and single core game designs

2013-01-28T13:23:27+02:00

And if you don't trust me :

I'm running a app that take 90-100% of one core.

Then I've launched several other app, closing stuff, ....

You can see in the graphics that windows is moving the app around to average the load over the cores.

I've put some numbers so you can follow it easily

Statistics: Posted by Ze_PilOt — 28 Jan 2013, 13:23

Re: Processor Affinity and single core game designs

2013-01-28T13:25:10+02:00

FA is not the only process using the core thus it runs at 100%. That is bad. I have made no claims about how processes are allocated to each core and I think your example is over simplified and invalid.

If load balancing does no harm you should use it for the benefits I have described above.

Statistics: Posted by ThinkTank — 28 Jan 2013, 13:23

Re: Processor Affinity and single core game designs

2013-01-28T13:12:52+02:00

To make a simpler example of what the article is describing.

Let's say you have 4 non-threaded applications, and four cores.

Each app (A, B, C, D) are using, each, 20% of one core.

If you are running all these apps at the same time, you probably will end up with :
core 0 : 80% CPU
core 1,2,3 : around 1-2%.

So moving each application over other cores (with process affinity) will result with :
core 1,2,3,4 at 20%

And probably less thermal problems on a laptop, yes.

Now, we are replacing A with an application that take 90% of your CPU. Let's call it FA.
By default, you will probably end up, on secven with :
Core 0 : 90% cpu
Core 1 : 60% (the other applications), or something similar.
Core 2,3 : 1-2%

Moving app A (FA) around won't change anything, you will just move the 90% of another core, but it will always take 90%. You can't make it less.

What you SHOULD do in that case is moving B C D in other core, so you end up with :
Core 0 : 90 % CPU
Core 1,2,3 : 20 %.

But overall, your laptop will (probably) generate the same thermal dissipation.

That's why I'm saying Core maximizer does nothing : FA take as much CPU as it can, you can't cut it in half.
While XP would try to run every app on core 0 (resulting in a slowdown), seven will already try to move stuff around, making thread affinity useless.

Statistics: Posted by Ze_PilOt — 28 Jan 2013, 13:12

Re: Processor Affinity and single core game designs

2013-01-28T13:21:11+02:00

That is not how Core maximizer works. I will also claim that if you manually set affinity to move FA.exe to the core1 you will still gain benefits because when the computer boots, it allocates processes to core0 and does not remove all of them when FA is loaded.

Statistics: Posted by ThinkTank — 28 Jan 2013, 13:06

Re: Processor Affinity and single core game designs

2013-01-28T13:05:08+02:00

ThinkTank wrote:
WinXT was a fine OS. I am saying Win7 can benefit from balancing too. IF the OS is balancing all of these tasks well, why remove one core by running it 100% and only give the OS 3 remaining cores to work with?

If FA is 100% on core 0, moving it to core 1 will make core 1 at 100%.

I don't see how you can reduce the overall charge doing that, sorry.

Statistics: Posted by Ze_PilOt — 28 Jan 2013, 13:05

Re: Processor Affinity and single core game designs

2013-01-28T13:06:00+02:00

WinXT was a fine OS. I am saying Win7 can benefit from balancing too. If the OS is balancing all of these tasks well, why remove one core by running it 100% and only give the OS 3 remaining cores to work with?

Statistics: Posted by ThinkTank — 28 Jan 2013, 13:03

Re: Processor Affinity and single core game designs

2013-01-28T13:02:17+02:00

ThinkTank wrote:
1. You use Windows XP and the benefits are greater there.

It's true that it will perform better.
But stop using XP (a twelve years old OS !!) will make your computer run better with everything, not only FA.

ThinkTank wrote:
2. You have a laptop and running one core at 100% and 20 degrees higher temps will cause your laptop to thermal throttle at an earlier threshold.

I don't own a laptop so it might be true. But loading FA on core 1 will probably take 100% of that core too, you are just moving the charge around.

ThinkTank wrote:
3. You believe load balancing your OS is a good thing. Having I/O, Networking, and PCI access balanced over multiple cores will maintain your sim speed when your computer struggles with Forged Alliance.

7 perform way better than XP on these specific points, and it's already balancing these over your cores.

The only case where I can see a real use of it is if you are running a livestream that encode your FA stream on a single core too. Then not having them on the same core can help (even I'm pretty sure seven will move one of the process on another core by itself).

It's probably more true if you are running multiple app that doesn't take much CPU. Then It will not balance it on other core. But that's not the case with FA.

Statistics: Posted by Ze_PilOt — 28 Jan 2013, 13:02