Set affinity?

[newtie]

Hi

How do you set affinity in the GTN750?

Didn't find anything in settings or utilities.

Mark

[RXP]

Hi Mark,

Why would you want to?

Have you noticed any problem when not manually changing the affinity?

[newtie]

I'm running HT and want to assign it to an unused core (s). In the .ini, it looks like 0 and 1 (auto) are the only available options that I could find. I'm looking for the code to have XP run as follows:

00,10,10,00

Also the protocol for setting it up in other configurations as well.

Thanks,

Mark

[RXP]

You've found the setting which permits changing the affinity if needed. Please note the comments in the file though, it is not limited to 0 or 1:

; selects the CPU running the trainer process: 1 to 32
; 0: last core, -1: automatic.
CpuAffinity = -1

The question remains:

3 hours ago, RXP said:

Have you noticed any problem when not manually changing the affinity?

In other words, are you wanting to change the affinity because you've been used to workaround other products limitations, or because of an actual performance (or other) issue with the Reality XP GTN?

In effect, unless there is a problem, there should be no need to change the affinity and keep the setting to 'automatic' (-1)

[newtie]

OK

What would CpuAffinity=?

If desired core assignment = 00,10,10,00?

Thanks

[newtie]

Apparently this support request is closed.

I'll figure this out another way.

Thanks anyway.

[RXP]

2 hours ago, newtie said:

Apparently this support request is closed.

Not having instant answer doesn't mean the topic is closed!

On April 25, 2018 at 8:56 AM, newtie said:

If desired core assignment = 00,10,10,00?

What do you mean with this?

The settings is easy, really, don't try over engineering this: you have a CPU with 6 cores, you can select:

• -1: automatic
• 0: last core
• 1 to 6 the core you want.

You have a cpu with 16 cores and want to run the trainer on core #13? CpuAffinity = 13

Can't be simpler than this. Again re-read the auto-commented line in the ini file:

; selects the CPU running the trainer process: 1 to 32

[newtie]

Thank you for the reply.

First,  00,10,10,00 is the binary masking of a four core processor with HT on (8 cores) allowing the GTN to run on unused cores 4 and 6 only. This was the essence of my question and my mistake as you might not be familiar with this. Masking is described here in detail if you'd like to know more.

Regarding your over engineering comment, P3D 4.2 has changed regarding how it manages threading. I never had any luck with HT in prior versions except a lot of heat. Not so with 4.2. I'm using an affinity mask of 213 with 4.2 (11,01,01,01) with extraordinary results. You can see what I'm trying to do with the XP based on that AM.

Second, the XP might not be capable of running in the configuration as described above which I think may be the case. If so, let me know and I'll go to plan B.

Thanks,

Mark

[RXP]

When you set your affinity mask, behind the scene, it uses SetProcessAffinityMask:
https://msdn.microsoft.com/en-us/library/windows/desktop/ms686223(v=vs.85).aspx

The RXP GTN CpuAffinity setting uses the same, and as you can infer, you can run the GTN on 1 core only (which is expected and fine).

In your use case, set GTN #1 for example to 3 and GTN #2 to 5 to fill the holes. You can cross check with sys internals "Process Explorer" the processes affinities (simulator, GTN1, GTN2) are actually correctly set when running.

[newtie]

Thank you.