Better LP0 Utilization Rate

[DonMuskopf 33]

Up until now, I have always had to lock my frame rate at 30 to 35 FPS to keep the LP0 utilization rate below 100% and free up CPU resources. The most effective way to this for me was setting the Max Frame Rate in NCP to 35 and setting the P3D Target Frame Rate to 120 FPS or Unlimited.

To my amazement in v5.3, I now find that if I turn off the Max Frame Rate setting in NCP and set the P3D Target Frame Rate to Unlimited, LP0 utilization drops from 100% when it was locked at 35, to 50% to 60% at unlimited.

I know this makes no sense, but this is what is happening for me. Can anyone else duplicate this?

What is happening, is that if you lock your FPS at less than the FPS you would get with the Target Frame Rate set to unlimited, then LP0 utilization will jump to 100%.

For example, if FPS is 50 when the Target Frame Rate is unlimited, but you had capped your FPS to say 40, LP0 utilization jumps to 100%. On the other hand, if you set your FPS above 50, say 60, LP0 utilization will drop significantly below 100%. So setting your Target Frame Rate to unlimited will keep your utilization below 100%, if your system is capable of it.

My AffinityMask=64853.

 

This is so strange, I almost didn’t post it. You know the saying “Better that people think you are dumb, than to open your mouth and erase all doubts”, lol.

 

 

 

[40track 80]

Tried it. Still stuttery. What i did was to delete the [jobscheduler] part then saved then tagged as read only then deleted any the old P3D cfg file and any backup in the directory then dropped the modded read only P3D.cfg back in. Smooth as. Glad you found what you wanted. Hope others do too.

 

Edited December 12, 2021 by 40track

[dave2013 1,151]

This didn't work for me.  Core 0 still maxed out at 100%.

I have a core i7 9700K with 8 cores, no HT.  I have the target frame rate unlocked in sim and use Nvidia settings to limit max frames to 33/sec.

I set my Affinity Mask and CoreP3DAffinityMask to 127, or 01111111, to avoid using core 0.  This setting did actually reduce the load on core 0 as its utilization stays between 90-95% most of the time, whereas before it was always 100%.  Now, if I don't limit frames to 33/sec using the Nvidia settings, core 0 stays pegged at 100%.  P3D loves using core 0.

I also tried setting the MainThreadScheduler to core 7, but as soon as P3D is started this setting is forced back to 0.

Dave

[Ikarus280 93]

I suffered from extremely long stutters mid flight, eventually leading to a complete freeze, hence I had to quit the simulator. 

LP0 was at 100%. There is a bug with the new version and LM is aware of it. Hopefully a fix will come soon.

https://www.prepar3d.com/forum/viewtopic.php?f=6315&t=143918&start=60

[Ikarus280 93]

I suffered from extremely long stutters mid flight, eventually leading to a complete freeze, hence I had to quit the simulator. 

LP0 was at 100%. There is a bug with the new version and LM is aware of it. Hopefully a fix will come soon.

https://www.prepar3d.com/forum/viewtopic.php?f=6315&t=143918&start=60

My FPS was locked to 33 via NCP. Have to find alternative solution until its fixed. 

[DonMuskopf 33]

Thanks for the replies, everyone. Just to be clear, I wasn't saying that what I discovered would stop the "long stutter" bug. My point was that doing the opposite of what we normally do to reduce a 100% LP0 utilization rate worked (at least for me).

Maybe it has something to do with G-sync and/or driver? I think this version of P3D is haunted, lol.

[Sparkrite 190]

2 hours ago, dave2013 said:

I set my Affinity Mask and CoreP3DAffinityMask to 127, or 01111111, to avoid using core 0

Surely this AM setting is avoiding core 7 and NOT core 0?

[Ikarus280 93]

4 minutes ago, Rob_Ainscough said:

Can you show me where LM indicated there is a bug and they are going to fix it?  I see Rob McCarthy (LM) asked for more information:

I don't see any confirmation there is a bug?

My process for problem diagnostics is to delete Prepar3d.cfg, disable all add-ons and see if the same issue persists.  If the problem goes away, then start adding Add-Ons one by one until you encounter the issue.  If the problem persists in a default configuration, then dial back all the graphics settings and test, increasing them with each increment until you get a "freeze".

 

I know this is work and a pain, but LM haven't confirmed a problem nor a fix so this is probably the best way to proceed.

Cheers, Rob.

 

Hi Rob,

Unfortunately, the issue is a bit more complicated than troubleshooting by removing all add ons and dialling back settings. The reason for this is because it does not happen on all flights, but on some of them usually during cruise. It usually begins with long stutters, and then a total freeze. 

That is why I did not run into the issue when tweaking P3D yesterday trying a variety of scenarios to find my sweetspot for graphics/performance. 

Some users reported that resetting the affinity mask to default fixes the issue, for others turning off EA helped. Will take a while to find what it is which is causing this.

I added this change for the jobscheduler:

[JobScheduler]
AffinityMask=4053
P3DCoreAffinityMask=4053
MainThreadScheduler=0
RenderThreadScheduler=1
FrameWorkerThreadScheduler=2

Flying without any AI or road traffic, departing from MK-Design EFHK. 

The bug does not happen on every flight, which makes it difficult to replicate. I'm also using the same settings and add ons as in 5.2, where I never had the issue. 

To answer your question, LM admitted that they are investigation on the last reply here:  https://prepar3d.com/forum/viewtopic.php?p=250521

"We are investigating this issue. Any additional details will help us find the root cause of the problem including departure location, add-ons installed, aircraft used, and settings. There is another post on this topic so to reduce confusion I'm locking this one and would ask that everyone please uses the following post for this issue: https://www.prepar3d.com/forum/viewtopic.php?f=6315&t=143918"

 

[dave2013 1,151]

1 hour ago, Sparkrite said:

Surely this AM setting is avoiding core 7 and NOT core 0?

Ah.  I know the least significant bit is the last one on the right, but I figured the order representing cores would be left to right.

So 11111110 would be 254.

I'll try that.

Thanks.

Dave

 

[dave2013 1,151]

Yep, 254 got everything off core0 and just shifted it all to core1.  Now core1 is almost always maxed out.

I thought P3D was supposed to use multiple cores more efficiently?

Thanks, Sparkrite.

Dave

[Ikarus280 93]

38 minutes ago, Rob_Ainscough said:

Yes, investigating and asking for details on how they can try to replication the problem.  That's not the same as found a problem, it's a bug, and going to fix it ... LM would communicate when/if they can replicate and have a solution.  They're in the gathering of information stage right now ... I just want to make sure folks don't get false expectations.

I see, my apologies. English is not my first language.. However on the bright side as many users are reporting this issue LM will prioritize it hopefully. 

One member from another thread reported that he fixed his issue by downloading project lasso, and then checking which cores P3D is using and which ones are unused.

I checked which cores P3D was using, and which ones were idle through PL. Then I assigned the affinity of other processes (active sky, SODE, navigraph simlink etc) to the cores P3D isn't using to free up some resources from the cores in use by P3D (especially LP0). I hope this fixes the problem and I will report back if it does, after a few flights. 

I noticed that my terrain textures are much sharper as well after this, but it might be a placebo. 

 

 

[Sparkrite 190]

3 minutes ago, Ikarus280 said:

English is not my first language..

Off topic, I know, but nevertheless......

Well let me be the first to congratulate you, with your written English, it would most certainly appear as if it is. 👍👍

[gaab 111]

I am not sure if this can help:

 - With default fresh installation, I get Lp0 at 100% even at the scenario screen (when one would expect a quasi idle system). This was also true with 5.2..

Only opening from there the "Option" panel stops this 100% Lp0.

I would appreciate if someone would be kind enought to tell if he see the same (simply looking at Task Manager after opening the scenario screen).

You can take a look here https://www.avsim.com/forums/topic/611522-mainthreadscheduler-core-at-always-100/

Gérard

Also for me, English is not first language 😉

 

[DonMuskopf 33]

 

Quote

I get Lp0 at 100% even at the scenario screen

Hi gaab,

At the scenario screen I get 1% on LP0. Hope that helps.

[gaab 111]

6 hours ago, DonMuskopf said:

 

Hi gaab,

At the scenario screen I get 1% on LP0. Hope that helps.

Yes and No 😉

This and other symptoms are pushing me toward a full Windows re-installation 😞

And I hate this idea..

Any way - thank you for taking the time to test and answer.

Gérard