[PBR] Sudden and large loss of FPS as sun sets
tracked
Dan Linden
Bug copied from https://jira.secondlife.com/browse/BUG-234859
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What just happened?
Using Second Life on Bellisseria as sun set. I had the Statistics bar up for PBR viewer testing. As the sun finally went down there was a visual change and a big drop in FPS, which did not recover afterwards.
FPS while sun was still up was approx 85fps, with a frame of around 11ms.
Immediately the sun finally set the FPS dropped to around 40FPs and the frame time jumped up to around 25ms. It stayed like that for some minutes.
Looking at the statistics bar about 5 minutes later the FPS was round 70 FS and frame time around 15ms.
What were you doing when it happened?
Watching the sun set on Bellisseria with Statistics bar open. Using Release candidate 7.1.2.7215179142.
What were you expecting to happen instead?
Frame rate to stay similar in all sun/moon conditions.
Other information
A relog after 5 minutes or so appears to allow the FPS to go back to around 85fps (frame time 11ms or so) rather than the limited FPS it had settled on ahead of the relog.
I had noticed during previous testing related to the NVidia GPU/8 core CPU systems on Firestorm and LL viewers that there could be a big an sudden change in FPS at times when sun was out and not. But the report as shown above was my clearest indication the frame rate drop was exactly as the sun finally left the sky and the sky turned a sudden deeper blue with no sun colour in it.
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Dan Linden
Thank you for the report, Ai!
Issue tracked. We have no estimate when it may be implemented. Please see future updates here.
Dan Linden
tracked
Dan Linden
ai.austin Ai Austin added a comment - 18/Dec/23 7:40 AM
I happened to catch the transition from sun just above the horizon to sun just below the horizon in Firestorm 7.1.1.72630 while I had the statistics bar open and that exhibits the same behaviour significant frame rate drop behaviours as the LL 7.1.2.7215179142 RC. 9ms frame time to 24ms frame time .
Images of Sun Up and Sun Down attached.
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dan.linden Dan Linden added a comment - 19/Dec/23 11:49 AM
I was going to say this sounds like BUG-234706, but you are already running the GLTF maint viewer in which this should be fixed.
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dan.linden Dan Linden added a comment - 20/Dec/23 10:38 AM - edited
It appears that parcel is using the default Day Cycle.
If you create a new Day Cycle from the + button in the Inventory, then open it and hit the Play button does this performance drop reproduce?
If it does reproduce, it would be interesting to note if the GPU utilization dropped as well. You can see this in the Performance tab of the Task Manager. This is what the issue was in BUG-234706.
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ai.austin Ai Austin added a comment - 22/Dec/23 12:40 PM - edited
Trying to get you that data Dan.
Incidentally though, the same FPS and frame rate drop occurs when the moon sets. See Moon-Up.png (94fps) and Moon-Down.png (instant drop to around 55FPS and a slow recover to about 60FPS, but not bouncing back up to the higher frame rate seen earlier.
Tested on current release, current RC and some nightly builds up to 21-Dec-2023 on Discord Content-Features Channel and it happens on them all. Also on latest Firestorm PBR Alpha. Seen on my two Windows 10 32GB memory Xeon processor systems (one with Nvidia GTX 1080 and one with Nvidia GTX 980).
Second_Life_7_1_2_7215179142_x86_64_Setup.exe
Second_Life_7_1_2_7267936070_x86_64_Setup.exe
Second_Life_7_1_2_7292896315_x86_64_Setup.exe
Phoenix-FirestormOS-Alphax64-7-1-1-72630_Setup.exe
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ai.austin Ai Austin added a comment - 22/Dec/23 1:15 PM - edited
New Day Cycle Test as Requested
Test on a machine while travelling, 32GB memory, Nvidia GTX 980 GPU (4GB). Wifi on this particular test, but I don't think that is relevant as its actually faster than my home broadband (Speedtest shows steady 150mbps down, 30mbps up). On a Bellisseria region on main grid, Set camera to look out to sea and horizon. Only a buoy in view.
Created a New Day Cycle and left it unchanged. Took a reading of GPU usage (high, but pretty level). SL Viewer running at 155FPS steady. Shared Environment still has sun high in sky at the time. See Before-New-Day-Cycle-Play.png
Opened New Day Cycle and hit play. FPS was around 120FPS at start of play, as Moon set it dropped to around 90fps, see During-New-Day-Cycle-Play.png. GPU usage was lower than before but not by much.
Then as new day cycle continued it recovered slowly back to around 120FPS and stayed around that figure during day part of cycle. Then as Sun set drop again to around 95fps, and slow recovered back to 120FPS. While play on the new day cycle was running it never went back to around 150FPS as it started at.
When I stopped the New Day Cycle Play and returned to Shared Environment. Sun still high in sky. FPS jumped back to 155fps.
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ai.austin Ai Austin added a comment - 03/Jan/24 4:40 AM - edited
For what its worth as additional information, I was running the Firestorm PBR Alpha 7.1.2.72848 on a Bellisseria region with shared environment at the time of a moonset so brought up the statistics tool.
The FPS was pretty stead around 77fps as the Moon was going down and while there were reflections in the water.
The moment the reflections in the water disappeared the frame rate dropped to 28 FPS. It stayed around there for about 2 minutes.
The frame rate very slowly nudged back up. 40FPS after about 5 minutes, 50 FPS after 10 minutes, but even much later it still had not returned to the original 77FPS.
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ai.austin Ai Austin added a comment - 13/Jan/24 7:43 AM - edited
Retesting on 7.1.3.7467259489 (GLTF PBR Maint 2) and I observe the same behaviour. View is past a Bellisseria houseboat out to sea to West. See 2024-01-13-SL-7.1.3.7467259489-Test-View.jpg
FPS as sun approaches horizon for sunset - 71 FPS
Sudden change as sun goes down - 43 FPS
After 4 minutes it has slowly risen to 52FPS
After 10 minutes it has risen a bit further to 62FPS and seemed to stick at that for 10 minutes more.
I then relogged back to same camera, window size, etc and FPS was instantly up at 85FPS.
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ai.austin Ai Austin added a comment - 15/Jan/24 1:49 AM - edited
I don't have a convenient Linden Lab pre-PBR viewer installed to test on that, but I did try on the pre-PBR Firestorm 6.6.17 and that does not show the FPS dip at sunset and moonset. The FPS stays pretty level throughout a day cycle.
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dan.linden Dan Linden added a comment - 19/Jan/24 10:54 AM
Thank you, Ai! I see the loss of FPS on my machine too.
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dan.linden Dan Linden added a comment - 25/Jan/24 10:45 AM
The dip in framerate here seems much larger when shadows are on. I do see a change in framerate on a pre-PBR viewer (6.6.16.6566955269) too, but the variance is smaller.
Ai Austin
Dan Linden This was originally spotted some time ago and reported as https://jira.secondlife.com/browse/BUG-234859 (copied here), but the issue is still present even as late as ExtraFPS viewer RCs such as Second Life Release 7.1.11.11750364439 (12-Nov-2024). Just today I saw a sudden drop from 85fps just before the sun set (same for moon set actually) to around 50fps immediately as that occurred. And as before recovery was very slow.