fixed Extreme, sudden and unrecoverable loss of FPS

[Flappie]

Context:

I was flying a Viggen in a private MP session with ~20 other players over Syria.

I did two Rb15 runs without any problem (two takeoffs from Larnaca, two landings at Larnaca).

After my second landing, I taxied to get close to the airport terminal/hub. I set master mode to BER (radar cut off, nav cut off) and parked. Mission had started 40 minutes earlier.

Symptoms:

Suddenly, my FPS were down to a ~3 FPS and it wouldn't get any better after 5 minutes. Same thing in F2 view, same thing after switching to F10 view and then swiching back to F1 view. It was simply unplayable and I had to leave the server and then come back.

DCS stats were saying "CPU bound".

In the task manager, 40% os my CPU was used.

I closed the Track IR app, but it didn't help. Windows was running just fine.

My buddies had no such issue.

PC:

• AMD 3700X
• 1080 Ti (11 GB VRAM)
• 32 GB RAM + 32 GB pagefile on SSD
• Pancake 3440x1440

 

Since my track is 40 minutes long, it will probably not be usable by devs. I'm looking for a rather short track showing the same issue: an extreme, sudden and unrecoverable FPS drop. If you encounter the same issue, please attach a short as possible track (SP is better).

options.lua

Edited June 16, 2023 by Flappie

[darkman222]

Thanks @Flappiefor creating the thread. I have track replays but they are from an obsolete DCS versions now so they wont help anymore.

Issue still persists. The easiest way to recreate it is (text copied from another thread I posted in):

• •  

• Author

Posted April 27 (edited)

My observations are:

-CPU frame time will degrade after time. Might be related to something that killed aircraft leave on the server. Possibly craters, or other leftovers of what ever kind, that will add up in the CPU frame time.

-Aircraft like the F18 or F14 that are CPU heavy will start suffering earlier than aircraft that are light on the CPU like the F16. But it will just take longer until the F16 will notice bad CPU frame times too.

What I did in that video:

On that specific server when I took the video there was not too many players online. So it took quite some time until the degradation started. 10 - 15 minutes maybe. When I went from guns area ( where the leftover of killed players is in a very dense area) to the BVR area (where the leftovers of killed players is less dense) the CPU frame time recovered. As soon as I went back to guns area frame time went back to the poor performance again. That means what ever causes the CPU frame time to degrade stays on the server the entire session.

-when I reconnect to the same server, go to the area that had bad performance, there is no initial performance loss. It just starts to add up again over time.

Here is a video illustrating what happens. Watch the CPU Frame time graph-

 

Edited June 16, 2023 by darkman222

[Flappie]

Thank you for your track. I'm unable to detect any FPS drop in your track (in 2D/pancake mode).

What happened to me was very different: it dropped from ~60 to ~3 FPS (extreme) in a handful of seconds (sudden), then it stayed at 3FPS until I left the mission (unrecoverable).

[Flappie]

Could that be an external program that was messing with your performance while you were flying?

I've tried my 45 minutes long track by the way, and I can reproduce the brutal FPS loss. Maybe it has something to do with the Viggen radar after all, because it wasn't off when FPS went down. I'll ask devs to take a look.

[darkman222]

OXR Toolkit method unfortunately does not work for me. I tried it a lot yesterday. And I am sure now, it does not work for me.
But we did a multiplayer flight with our squadron yesterday. And one of 4 people encountered a massive frame drop. like at 3fps. While nobody else did. He was suspecting the TGP, but were not sure as his winman used his TGP as well without degradation.

2 people in VR, 2 in 2D. Frame drop was for the guy in 2D.

Edited June 17, 2023 by darkman222

[Flappie]

20 minutes ago, darkman222 said:

But we did a multiplayer flight with our squadron yesterday. And one of 4 people encountered a massive frame drop. like at 3fps. While nobody else did. He was suspecting the TGP, but were not sure as his winman used his TGP as well without degradation.

Did his FPS ever went up again, or was he forced to leave the server? I'm interested in his track, if he still has it (in "Saved Games/Tracks/Multiplayer"). Which aircraft was it?

[Art-J]

1 hour ago, gortex said:

There is a map I run where the fighting is north of Creech, so there is no water.  I turned off all the clouds, too. 

Just a sidenote - keep in mind the water layer in DCS is always continuously rendered below the whole map (and thus affects performance accordingly) no matter if you see it or not.

[darkman222]

On 6/17/2023 at 2:50 PM, Flappie said:

Did his FPS ever went up again, or was he forced to leave the server? I'm interested in his track, if he still has it

No, he had to leave the server. It was 4 F16s in total player controlled. The FPS were still fine until the end for everybody else. I will ask him if he still has the track.

[darkman222]

False alarm. He figured out. It was OBS recording software interfering with DCS

Edited June 19, 2023 by darkman222

[darkman222]

On 6/16/2023 at 4:36 PM, gortex said:

can reproduce it in a couple minutes in single-player.

Your frame test ran fine on my system. Cant confirm that one.

[darkman222]

VR for me too. Specs with Varjo Aero. Not the worst system

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[Nealius]

On 6/19/2023 at 9:25 PM, darkman222 said:

False alarm. He figured out. It was OBS recording software interfering with DCS

Got any more details? I record my flying in OBS quite often and frequently encounter the same issue. Just now I landed and my framerates plummeted to 1fps, with performance showing 28% GPU usage, 60% CPU usage, and DCS was accessing a bunch of Oculus hand tracking / eye tracking / body tracking files for some reason. It's getting really frustrating with these constant framerate crashes.

[Flappie]

My problem was caused by a specific bug at the Larnaca airbase, when one would approach the terminal. It's just been fixed internally.