CPU Usage up, GPU usage down results in worse performance.

[Ray Proudfoot]

Some info to back up my earlier post.

This is with both default Ai and AIG enabled but FSUIPC removing aircraft until 30fps is reached. Final Ai count was 35.



Next is no AIG Ai, just default Ai.



Finally, no AIG or default Ai.



The clear improvement is obvious. And just to reiterate... all World / Scenery Object sliders were set fully left for these three tests.

[Ray Proudfoot]

I need to make an admission. In the P3D.cfg I entered [Job Scheduler] instead of [JobScheduler] so the AF setting of 1365 was ignored.

That has now been corrected but shouldn’t impact on my tests this morning showing a substantial reduction of core0 with no BGL sourced Ai loaded into the sim.

After all, there must be quite a few people who don’t go into this degree of tweaking for optimal performance.

[TextRich]

Final test was zero scenery objects and no Ai at all, not even default. The result was a return to 5.1 performance. 100% core 0 hit only every 20-30 secs. 30fps maintained throughout. Fluidity!!

So it looks to me as though Ai is the culprit - even the default stuff. If anyone would like to try two tests - with and without default Ai and disable their 3rd party Ai that would be helpful.

Disclosure: I have an i5-10600K. I just tried your test and still get CPU0 at 100% even with all World Scenery sliders to the left and no default AI traffic of any kind. I do not use any third party traffic. If I overlooked another default P3D setting that doesn't involve editing .cfg files, let me know.

[Ray Proudfoot]

@TextRich, what do you have set for your Affinity Mask? How the CPU handles P3D is very dependent on that setting.

Check if you have a [JobScheduler] section in prepar3d.cfg.

[TextRich]

@TextRich, what do you have set for your Affinity Mask? How the CPU handles P3D is very dependent on that setting.

Check if you have a [JobScheduler] section in prepar3d.cfg.

I don't have a JobScheduler. I can try using the Expert Mode of this calculator:
https://www.gfsg.co.uk/affinitymask.asp ... m=utilties

Should HyperThreading in my system be off or on? I think it is on right now but I'll have to check the UEFI.

[Ray Proudfoot]

Opinions vary on whether HT is best on or off. My professionally build CHILLBLAST has it on and performance on P3D v4 and v5.1 was always fine for me.

All the logical cores on your CPU will be used. Limiting it to only one per physical core should help performance. Your CPU has 6 cores like mine so if HT is on enter the same value as mine.

[JobScheduler]
AffinityMask=1365.

[TextRich]

Opinions vary on whether HT is best on or off. My professionally build CHILLBLAST has it on and performance on P3D v4 and v5.1 was always fine for me.

All the logical cores on your CPU will be used. Limiting it to only one per physical core should help performance. Your CPU has 6 cores like mine so if HT is on enter the same value as mine.

[JobScheduler]
AffinityMask=1365.

I tried it with HyperThreading disabled but it didn't look any good so I stuck with HT enabled.

No matter what AM I tried, including yours Ray, I was not able to get the first thread to not look like it is above 100% most of the time. I wonder if it is a fundamental difference between our two processors.

Rather than upload a bunch of images, I'll summarize in text:

Note that I believe AM 1365 is for 6 non-HyperThreaded cores. The online calculator has a different checkbox for HyperThreaded cores with different AM values.

Note that CPU 0 = 1st thread and CPU 11 = 12th thread. If six cores and no HT, CPU 0 to CPU 5. If six cores and HT, CPU 0 to CPU 11.

a) HT On, AM 1365 = 1st thread at 100% most of the time, 3rd, 7th, and 11th very busy, 5th and 9th a little busy, 40% CPU utilization.
b) My default, HT on, no AM = 1st thread at 100%, 2nd, 4th, 6th, 7th, 8th, 9th, 10th, 11th, 12th very busy, 3rd and 5th a little busy (all cores are used), 66% CPU Utilization
c) HT On, HT Core 0 selected = 1st thread not used much, 2nd (also in Core 0) at 100%, 4th, 8th, 12th very busy, 41% CPU utilization
d) HT On, No Core 0 selected = 4th, 6th, and 10th at 100% most of the time, 1st and 8th used a little bit, 29% CPU utilization
e) HT On, but Core 0 not HT, No Core 0 selected = only 11 threads, 4th at 100%, 6th and 9th slightly below 100%, 1st and 8th a little busy, 32% CPU utilization
f) HT On, but Core 0 not HT, Physical Core 0 selected = 11 threads, 1st at 100%, 4th and 8th very busy, 2nd and 3rd somewhat busy, everything else a little busy, 27% CPU utilization
g) HT Off, Core 0 selected = 6 threads, 2nd, 3rd, and 6th at 100%, other 3 a little busy, 63% CPU utilization
h) HT Off, Core 0 not selected = 6 threads, 1st at 100%, 2nd, 4th, and 6th very busy, 71% CPU utilization

What should I prioritize until the hotfix? All 12 threads/CPUs being used by the sim (which would be (b) at 66% CPU utilization)? Or go with less utilization? If I do the latter I would use (d) over (e) and (f) since I wouldn't need to turn off HT for Core 0 in my UEFI. What do you think?

[Ray Proudfoot]

@TextRich. That’s too much info to absorb, sorry. Your i5 will not be as powerful as an i7 but the principal remains the same. With HT on use virtual processors 0,2,4,6,8 and 10.

That’s 010101010101 in binary which equates to 1365 in decimal. Enter that value in AM in P3D.cfg and that’s as good as it will get.

[TextRich]

@TextRich. That’s too much info to absorb, sorry. Your i5 will not be as powerful as an i7 but the principal remains the same. With HT on use virtual processors 0,2,4,6,8 and 10.

That’s 010101010101 in binary which equates to 1365 in decimal. Enter that value in AM in P3D.cfg and that’s as good as it will get.

OK fair enough. A couple of questions:

Why not virtual processors 1, 3, 5, 7, 9, and 11 (101010101010, AffinityMask=2730)? Is it because those virtual processors only exist as a result of hyperthreading?

Why not all virtual processors 0 to 11 (111111111111, AffinityMask=4095)? Use all 12 processors? Does P3D do that anyway by default?

[Ray Proudfoot]

@TextRich, with respect this is a topic about a problem running v5.2 and the impact of Ai Traffic.

If you need help about setting the AM please raise a separate topic.

[TextRich]

@TextRich, with respect this is a topic about a problem running v5.2 and the impact of Ai Traffic.

If you need help about setting the AM please raise a separate topic.

I wasn't asking for assistance in my last post. These were rhetorical questions in an attempt to understand v5.2's performance together. Sorry to sound otherwise.

[SimForLife]

Ok Team: After reading all of these posts relevant to CPU usage Versus GPU usage. I made the decision to completely wipeout my New PC, reformatted my SSD's and reinstalled Windows 10, made sure I had all of the Window updates, I downloaded P3DV5.2 clean no add-ons, loaded a flight out of NYC - KLGA - using the F-22 - flew around the city and it's obvious this version is using more CPU than GPU - however, I'm just hitting between 55%-75% utilization on the CPU and bearly touching my GPU at 3-4% utilization. I've push all of the settings to the extreme left bear bones and the CPU utilization maybe dropped by 5-10%, push settings all the way to the right max everything and my CPU utilization increase to 89%-100% and that's not using any add-ons, yet with both scenerios my GPU utilization never went passed 12% utilization. Hope this helps the Lockheed team with a future Hot Fix Update.

Regards
Peter

[Ray Proudfoot]

Peter,

We need to know your hardware specs. Also, did you set an Affinity Mask value? In my tests it wasn’t active due to a typo but with it set to 1365 yesterday results were much improved.

It appears critical to proper P3D operation so should be a mandatory setting in the P3D.cfg. But only the user can enter it since it’s CPU dependent. But how many users have it set Certainly not Joe Public. Maybe just the enthusiasts.

[Ray Proudfoot]

I have resolved the problem and here's how simple it was. There's one critical setting that has solved things. My thanks to SteveW on AvSim for pointing out the typo.

[JOBSCHEDULER]
AffinityMask=1365

I had entered this in P3d.cfg but crucially included a space in the section name. So the AM was ignored. So by default every logical processor was being used. This resulted in my 6-core, 12 logical processor CPU being swamped with demand from P3D on the critical core 0. Hence why even very low scenery settings were still causing cpu 0 to hit 100% and remain there for my test. That resulted in loss of fps and generally very poor performance.

It only recovered to under 100% when I removed all Traffic BGLs including the default stuff. But who wants to fly in a sterile environment?

Having had the typo pointed out to me I corrected it and fired up P3D again. What a transformation. With the AM setting my CPU is now using the following cores for P3D.

0,2,4,6,8,10.

The second logical processor on each core is not being used. This is especially important for core 0.

My aircraft is now located 300ft above SimWings EGLL and is slowly slewing through 360 degrees. CPU0 rarely hits 100% and on average is around 80-90%. There are 85 AIG Ai in the sim. I use FSUIPC to reduce Ai if 30fps cannot be achieved.

I'm well versed with updating P3D and feel the wipe and reinstall is only required if you have serious probelems you can't resolve.

So there you have it. My BIOS has HyperThreading enabled but whether it has or not the importance of the AffinityMask setting cannot be overstated. It would be interesting to know if those of you with the same problem have that setting. If you don't then you need to calculate the AM value depending on how many cores your CPU has and whether HyperThreading is enabled or not in your BIOS.

Remember it's recommended Prepar3d.cfg is deleted and a new one allowed to be generated but crucially it won't have the AM setting in it. That has to be added manually.

[Ray Proudfoot]

TextRich, the i5 is the reason you're stuck at 100%. P3D really benefits from an i7 or faster.

Try adjusting your settings if you want to keep cpu0 below 100%. I found that when it was hit there would be a drop in performance albeit briefly. 100% on either the CPU or GPU means the hardware cannot deliver what you're asking in your settings.