Sign in to follow this  
jcomm

AffinityMask=15 on a 2500....

Recommended Posts

With FSX I always used AM=14 in FSX.CFG.

 

Yesterday after installing LMP3Dv2.2, I set no value initially and experienced some stuttering ( not only on the first flights ).

 

Later I decided to set my only tweak in the Prepar3d.cfg file, adding

 

[jobscheduler]

Affinitymask=14

 

and the ride was a lot smoother, but I still noticed a few fluctuations in fps under various heavy weather situations, so, I set it at 15, and... placebo or not ( I think NOT ) the fact is that I feel it a lot smoother now?

 

What are users with 8 cores using?

Edited by n4gix
Corrected [jobscheduller] typo

Share this post


Link to post
Help AVSIM continue to serve you!
Please donate today!

... placebo or not ( I think NOT )

 

Absolutely NOT... forcing all four cores makes a vast difference to terrain loading and smoothness for me too. Same CPU as yours.

Share this post


Link to post

If you saw changes with 14 that is a placebo.

 

Maybe LM will rethink the theory that allocating one core of 4 to Windows is good. One core of eight may be beneficial.

Share this post


Link to post

Hi jcomm,

 

With FSX I always used AM=14 in FSX.CFG.

 

Yesterday after installing LMP3Dv2.2, I set no value initially and experienced some stuttering ( not only on the first flights ).

 

Later I decided to set my only tweak in the Prepar3d.cfg file, adding

 

[jobscheduller]

Affinitymask=14

 

and the ride was a lot smoother, but I still noticed a few fluctuations in fps under various heavy weather situations, so, I set it at 15, and... placebo or not ( I think NOT ) the fact is that I feel it a lot smoother now?

 

What are users with 8 cores using?

Hi jcomm,

 

You might wish to remove the extra 'l' from [jobscheduller] in case some decide to cut and paste this entry into their Prepar3D.CFG and then wonder why it's not working ;)

 

Regards,

Mike

  • Upvote 1

Share this post


Link to post

Just to check my own tweak; I have an i7 4770k (and my task manager shows 8 cores) and I use:

 

[JOBSCHEDULER]
AffinityMask=15
 
Is that right?
 
EDIT: just had a look at task manager while in flight, and only 4 of the 8 cores shown are at work..  :huh:

Share this post


Link to post

Affinity Mask 15 is for using 100% of 4 Cores, if you have 8, you need some other value. I don't know which, but it isn't 15

Share this post


Link to post

EDIT: just had a look at task manager while in flight, and only 4 of the 8 cores shown are at work..  :huh:

 

Your 4770K has 4 cores. The task manager shows 8 threads because you have Hyper-Threading on.

Share this post


Link to post

So if hyperthreading is on is 8 threads meaning that you need to set an AF for 4 cores or 8?

 

Also ht is supposed to be on for fsx but off for p3d, is that right?

 

Alex

Share this post


Link to post

HT shouldn't be used on neither FSX or Prepar3d as far as I know. Turn it off, it will make your CPU run cooler, more stable as well!

Share this post


Link to post

I get best performance (on a 4770k) by enabling HT in the BIOS, but only including the physical cores in the affinity mask. The AM for that is 85.

Share this post


Link to post

So I tried with both AM=15 and AM=85 on my i74770k with hyperthreading on (8 threads). 

 

With AM=15 threads 1-4 in taskmanager are working.

With AM=85 threads 1, 3, 5 and 7 are working. 

 

In both cases 4 threads/cores seem to be working with P3DV2 and I did not notice any difference in performance.

Share this post


Link to post

I'd say the equivalent to AM=15 on 8 cores would be AM=255 ?

 

Mike, thx for the note on the typo, and n4gix, thx for having fixed it ;-)

Share this post


Link to post

Is anyone else seeing that using AF=15, core 0 is constantly at 100% while the other cores are hardly at 30%? Could mean that core 0 is some sort of bottleneck?

Share this post


Link to post

 

 


Could mean that core 0 is some sort of bottleneck?

 

Core0 is handling everything elso that you have going on, not just P3D, your OS has to run somewhere, and guess where that is, yep core0.

That is why if you have a lot running alongside the Sim then  AF14 is probably the way to go.

LM seems to agree

Share this post


Link to post

I'd say the equivalent to AM=15 on 8 cores would be AM=255 ?

 

Indeed, if you want to use all 8 cores/threads, 255 is the correct value.

 

Is anyone else seeing that using AF=15, core 0 is constantly at 100% while the other cores are hardly at 30%? Could mean that core 0 is some sort of bottleneck?

 

Most of the workload is still handled by the main thread which can make Prepar3D bound to the first core. This is why I think it's necessary that more stuff gets threaded out.

Share this post


Link to post

Try experimenting with AF=85 with HT on - that gives you 1 thread per physical core. And that way you can keep HT for any windows apps that can take advantage of it. 

Share this post


Link to post

Yeah, seems logical now. Would be nice if for instance core2 could be used as main thread, with the remainder of core0 being used as some sort of headroom. Probably easier said than done, but I am not that into the technical detail stuff ;-)

AF = 15 did solve a bit of the blurry problems I was experiencing, so it's going to be a tradeoff I guess.

I have HT turned off because I could not get my OC to be stable with HT enabled.

Share this post


Link to post

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this