A Frame-Time Analysis of P3D v3 -- Effects of CPU Affinity, Frame Lock, and HT

[captain420 3,099]

Mike, but with AM=116 it's giving me blurries in P3D :(

[Cruachan 705]

Strange just loaded up my sim and textures were all blurry with AF=116... So I removed AF settings all together and it was sharp again.

 

Any idea why setting AM=116 causes blurries? I thought that this setting would be optimal for me? Even with AM=253/254 I didn't get blurries.

 

But both a setting of 84 and 116 results in blurries.

It is likely that you have hit the barrier and run out of system resources to handle the settings as defined in your current Prepar3D.cfg. If I were you I would backup Prepar3D.cfg and then delete the original file. Run P3D and it will create a fresh file. Don't change anything meantime; just observe how the sim performs. If all is well and texture loading is executing efficiently without the appearance of blurries then exit the sim, add the AM = 116 line as it appears in the backup file and try running the sim again. Assuming things are still fine then begin moving sliders in single step increments to the right and test following each change. Be methodical and and be sure to use the same scenario each time during testing.

 

Edit: in the end you may need to experiment with other AM values. Perhaps 253 would be a better choice for your setup since you have observed that it seems to allow better handling of texture loading.

Mike

[Skywolf 992]

Hey all,

 

Can we use this site for calculation http://www.gatwick-fsg.org.uk/affinitymask.aspx?SubMenuItem=hardware

 

for the longest time i was confused on why all discussions were Logical Processors and not Threads.  I realized then core 0 is LP 0 and LP 1.  Super confusing.

 

I need to save some annoying VAS, and I believe HT on (using AM 255 or 253) is probably taking more VAS than just plain ole cores to p3d.

 

Based on what I am reading from all the discussion here (and Focus for the questions below is for CPU greater than quad core.  I have 6 core)

 

Q1) If HT is OFF - The P3D should be offloaded to 4 cores as long as it is on Core 0.  Like AM=30 (All physical cores 1,2,3,4 leaving cores 0, 5 free) or AM=15 leaving Cores 5 and 6 free

 

Q2) If HT is ON - Then P3D should be offloaded to 4 Cores with HT on (AM=255 This would be Core 0 (Logical 0, Thread 0), Core 1 (Logical 1, Thread 1), Core 2 (Logical 2, Thread 2), Core 3 (Logical 3, Thread 3) - all enabled) and or AM=253 Core 0 (Logical 0, Thread 0-SET to OFF), Core 1 (Logical 1, Thread 1), Core 2 (Logical 2, Thread 2), Core 3 (Logical 3, Thread 3) .

 

All addons like AS16+ASCA - I can use task manager to set their affinity to the Last cores 5 or 6 or just single core.

 

Is my understanding correct so far? 

 

Does P3Dv3 need Core 0 (Logical 0, thread 0 both or just Logical 0) or not?

 

Thanks

[captain420 3,099]

How can you set the affinity mask for a certain app using Task Manager?

[Skywolf 992]

How can you set the affinity mask for a certain app using Task Manager?

 

Open Task manager - go to Details and then highlight the app and click on affinity.  It will show all the cores or whatever is set.  You can uncheck or check on what you want and then click ok

[SteveW 1,792]

How can you set the affinity mask for a certain app using Task Manager?

Remember that certain apps like P3D lay out their affinity setup when they start. So if you start P3D with no AM, and subsequently uncheck Affinity CPU boxes in Task Manager, jobs already started are moved onto unmasked cores, doubling up processes on other cores.

 

In other words, apps that set their own affinity up should be left to do so themselves, do not reassign their affinity through Task Manager or other apps.

 

 

For the six core and P3D I set P3D with an AM=1365=01,01,01,01,01,01 and I set all addons to LPs 9 & 11 = 2560 Dec = A00 Hex = 10,10,00,00,00,00 Bin

 

(Note: I use commas in the binary representation to delimit core LP pairs when specifying for HT=On)

[cavaricooper 2,613]

I have read and re-read this thread, but am still left scratching my head.  I am running a 6700K at 4.6gHz with HT enabled.  I would like to keep the first actual and virtual cores free for another program that runs on my sim machine.  I have been using AM=84 with good results, however, I would certainly appreciate any input on this issue.  Is there some other AM setting I ought to try?

 

Ta!

[gboz 157]

 

 

Is there some other AM setting I ought to try?

 

Give 116 or 252 a try.

 

gb.

[cavaricooper 2,613]

gb-

 

Whilst I appreciate the suggestion, could you perhaps educate me as to why?  I cannot wrap my head around this topic :( Ta!

 

 

Give 116 or 252 a try.

 

gb.

[SteveW 1,792]

I would like to keep the first actual and virtual cores free

Think of them as the first two Logical Processors (LPs), that is the proper nomenclature. There is one actual core utilised as a pair of virtual cores.

[cavaricooper 2,613]

Steve-

 

Ok, thanks... Is there an AM that definitively leaves the first two LPs free?  Is it 84, 85, 116 or 252?

Ta!

C

[Cruachan 705]

Ok, thanks... Is there an AM that definitively leaves the first two LPs free?  Is it 84, 85, 116 or 252?

 

84 = 01010100

116 = 01110100

252 = 11111100

 

Mike

[SteveW 1,792]

116=01,11,01,00 the pair of zeros on right refer to the pair of Logical Processors on core zero. There are four LPs unmasked. You can improve scenery loading speed with AM=244=11,11,01,00 this gives a pair of LPs sharing bandwidth of core 3 to scenery loading, rather than giving one LP on core 3 maximum bandwidth with 116. Sharing core 3 depends on the type of scenery prevailing in the scene. You can share the rendering bandwidth on core 1 with the second sim job and increase scenery loading LPs to three using AM=252=11,11,11,00 you can see that sharing the rendering job with the second job (LP2 and LP3 on core 1) would reduce the rendering performance slightly, whereas 116 and 244 do not.

 

 

(Note: we are discussing four core with HT enabled and the explicit requirement to utilise only three cores for the sim, leaving one free of the sim for other purposes.)

[cavaricooper 2,613]

Thank you ALL, for your patience and kindness.  So, if I understand correctly, the best selection for my particular need to leave the first 2 LPs free and get the most fluid performance out of P3D (6700K with HT on) is AM=252 (or is it AM=244)?

 

Ta!

[SteveW 1,792]

Yes those are good if you need one core free, that free core is where the other apps would naturally find room to run.

 

Remember you can use all four cores for the sim, so that the sim also uses core zero, but instead with apps running alongside the sim you ensure that these apps don't run on core zero.

 

If they don't manage core affinity themselves, start them with a .bat file or manage them with another app, or move them off of core zero with Task Manager.