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

[grandfred29 180]

Hello steveW

 

i want to know if it s possible to put automatically the addon like asn, patcx and other on core0 ?

 

thanks

[SteveW 1,792]

and what about fftf0.1

FIBER_FRAME_TIME_FRACTION defines the percentage of each frame that is devoted to loading scenery:

 

Prepar3D.cfg

[MAIN]

FIBER_FRAME_TIME_FRACTION=0.33

 

0.1 and 0.2 can be tried with the possibility of improved fps for reduced scenery loading performance. Reducing from default may not be so good with very complex scenes and produce blurring.

[SteveW 1,792]

Hello steveW

 

i want to know if it s possible to put automatically the addon like asn, patcx and other on core0 ?

 

thanks

Warning: Complicated

 

Forcing an application with multithreading and network i/o to use only one core, may be a mistake and cause the app to stall. P3D and FSX addons using simconnect are using network i/o. Generally always provide at least two cores (be that HT cores or physical cores) to avoid problems.

 

If the application does not configure itself for the Windows Jobsheduler, the system will spread it out across the cores. An external application can be used to provide an Affinity Mask for an app to disable Logical Processors (I prefer to call "cores" or "HT cores" "LP"s). This must start the app so that the application "sees" this "affinity space" beforehand, or we can alter the application affinity once it has started.

 

With Task manager we can reassign affinity to an app, but certain apps like P3D and FSX do not respond in the same way as they do when started with affinity. P3D and FSX are best started up initially within an affinity space.

 

There are apps (e.g. Process Lasso) that can mess with application affinity, but I'm not sure how they work without study. Given the context of the question, I perhaps can mention that Ideal Flight 10 presents P3D and FSX with an affinity space so that they operate correctly, but that's specifically designed with the intention of handling the simulation to its best advantage. The next update to IF10 provides affinity control for all apps started with the simulator, which enables ASN to be started wherever we like. It is times like this that the value of the 6 core (or more) comes into the fore. With the four core, we are at odds; we want 4 cores for the sim and at least two cores for ASN. So we must mix the use of cores between the addon and the sim. We may do well if we can start the addons on cores 1,2,3, and run the sim on cores 0,1,2,3. If we turn on HT we can assign two LPs of the same core to ASN. Look forward to the next HEDT 6 core.

[GHarrall 494]

Warning: Complicated

 

Forcing an application with multithreading and network i/o to use only one core, may be a mistake and cause the app to stall. P3D and FSX addons using simconnect are using network i/o. Generally always provide at least two cores (be that HT cores or physical cores) to avoid problems.

 

If the application does not configure itself for the Windows Jobsheduler, the system will spread it out across the cores. An external application can be used to provide an Affinity Mask for an app to disable Logical Processors (I prefer to call "cores" or "HT cores" "LP"s). This must start the app so that the application "sees" this "affinity space" beforehand, or we can alter the application affinity once it has started.

 

With Task manager we can reassign affinity to an app, but certain apps like P3D and FSX do not respond in the same way as they do when started with affinity. P3D and FSX are best started up initially within an affinity space.

 

There are apps (e.g. Process Lasso) that can mess with application affinity, but I'm not sure how they work without study. Given the context of the question, I perhaps can mention that Ideal Flight 10 presents P3D and FSX with an affinity space so that they operate correctly, but that's specifically designed with the intention of handling the simulation to its best advantage. The next update to IF10 provides affinity control for all apps started with the simulator, which enables ASN to be started wherever we like. It is times like this that the value of the 6 core (or more) comes into the fore. With the four core, we are at odds; we want 4 cores for the sim and at least two cores for ASN. So we must mix the use of cores between the addon and the sim. We may do well if we can start the addons on cores 1,2,3, and run the sim on cores 0,1,2,3. If we turn on HT we can assign two LPs of the same core to ASN. Look forward to the next HEDT 6 core.

 

Hi Steve,

 

I have been following the affinity discussion regarding P3D v3 and have done some experimentation that shows your reasoning of using AF=85 with a 4 core HT enabled CPU to be the best option.

 

I havent tried this in my FSX install yet, but I have always used an AF which frees the first core for addons like the Q400, Opus etc.

 

If the addons can be distributed better across the cores other than 0, does your logic of 85 also work in FSX? In other words, if I applied 85 to my FSX installation does it work the same way as P3D does?

[SteveW 1,792]

FSX and P3D are very similar and can be treated the same with respect to the Affinity Mask.

[nicksort 8]

Steve - Just a quick update on the AM discussion you and I had last week by PM when I asked about my new 5930 build.

Motherboard: Rampage V Extreme

Processor: 5930K

Memory (part number): G.SKILL Ripjaws 4 3000C15Q-16GRR

Graphics Card #1: Titan

Graphics Card #2: Titan

CPU Cooler: Kraken X61

Case: R5

OC to 4.5MHz 67deg while in full load

I did try your suggestion of AM 340 vs 212 and yes it did exactly what you had said.

I was able to test KLAX to KSFO, Orbx Southern California, Dreamteam KLAX and FlightBeam KSFO-HD, MyTraffic6 set at 10% and P3dv3.1 Building Storms weather.

PMDG 737

I did a day flight and also a Dusk to Dark flight, at cruise level 12000ft

 

Results were good, NO Vas issues, No crashes and No problems.

4K @30htz

Ground frame rates were 15-20 no stutters.

In air frame rates were steady 20 and up and no stutters.

 

Considering ORBX Southern California and KLAX and KSFO are hard hitting on frames I was very happy with the results...

 

Thank you, Nick

[SteveW 1,792]

Hey Nick, thanks for letting me know. Glad to hear your setup is going well.  

[grandfred29 180]

thanks steveW for your answer, however i wish another answer for this question

 

i follow the setup for p3d.cfg display in the learning center, just set am=14 & fftf=0.25

 

i flown btw paris and sao polo, 11h30 flight, the arrival was done in bad weather and when i was align front of the runway i was be able to see the rw light and all the rest of sbgr scenery was totaly blurry, i wait about 15secondes and the scenery appear

 

so what can i change to resolve it?

 

thanks

 

hardware, cpu 4790@ 4.7, gpu 980ti oc..

[SteveW 1,792]

"am=14 & fftf=0.25"

 

am=14 is appropriate for 4 core HT=Off or 2 core HT=On

 

with 4790 try HT on and AM=85 or AM=116

 

fftf=0.25 Reducing from default 0.33 may not be so good with very complex scenes and produce blurring.

[funkyj4ever 2]

When i change TESSELLATION_FACTOR to 35 it resets back to 85?

[SteveW 1,792]

Yes, some values will change back to default if you go and make a setting with the Display Settings in P3D.

[Mbergsma 1]

Can someone analyze these 2 for me, especially curious what happens in picture one where AF= set to 85

 

 

 

 

 

 

 

I7 6700K

MSI GTX980 Ti

FPS= locked @31 HT=on AF=116

 

Thanks,

 

Marinus.

[pincopanco 5]

thanks steveW for your answer, however i wish another answer for this question

 

i follow the setup for p3d.cfg display in the learning center, just set am=14 & fftf=0.25

 

i flown btw paris and sao polo, 11h30 flight, the arrival was done in bad weather and when i was align front of the runway i was be able to see the rw light and all the rest of sbgr scenery was totaly blurry, i wait about 15secondes and the scenery appear

 

so what can i change to resolve it?

 

thanks

 

hardware, cpu 4790@ 4.7, gpu 980ti oc..

AM=14: blurry guaranteed.

With HT off, no AM.

[SteveW 1,792]

The top graph shows the sim main thread core being utilised by another program. In the case of 85 that would indicate an app on core zero. So you are good to go with 116 which avoids core zero. You can only rob Peter to pay Paul. If you run on four cores, the app must run somewhere on those too. Depending on how aggressive the app is, you may have to leave it on core zero, or let it mix with sim threads. The advantage here of HT enabled, means you can allocate two LPs to the app on core zero, with HT disabled it can only have one LP on core 0.

[ankh21 17]

AM=14: blurry guaranteed.

With HT off, no AM.

 

Mh, now i am confused.

 

HT off, 4 Cores, and i want to free core 0 cause other apps will run on this core, i have to put AM=14 inside the .cfg, or P3D will run on the first core and conflict with other apps?!

 

Matthias