Grimrock

I've been playing Grimrock 2 for a while now. I'd say I'm solidly mid-game at this point (I have forged three of the elements at the temples so far), and I'm noticing a general trend towards something that I think might be a performance bug of some kind.

Most of the time the game plays at a smooth frame rate with good input response. But occasionally, randomly, intermittently, its frame rate will drop significantly and there will be an intolerable amount of input lag. It becomes very slow and stuttery.

This, I have noticed, does not seem to be related to the graphics on the screen at the time. For example, sometimes I am cruising outdoors with a far draw distance and the frame rate is fine. Sometimes it is choppy. This is for the *same areas*. The same goes for when I am in a narrow dungeon corridor with very little on the screen and a very near draw distance. Sometimes the frame rate is fine, sometimes it is very choppy/stuttery.

It does not seem to matter if I play the game at full screen 1920x1080, or if I reduce the screen to windowed mode 1368x768. The problem happens equally either way, and it's just as random and intermittent.

Normally I would chalk it up to just "I need a better video card", except, that most of the time the game plays just fine, and the stuttering doesn't seem to be related to graphical complexity. Some of the most complex outdoor scenes are just fine on this game most of the time, except when the stuttering is happening.

When the stuttering happens, sometimes if I wait it will just suddenly go away after a little while. Another thing that will make it go away is loading up a saved game.

I have looked in the Windows Task Manager to see if there are any other processes taking up CPU time during the bad moments, and there isn't anything unusual happening or running at the time.

Here are my system specs:

Computer system: Sony Vaio Flip 15 laptop SVF15N2ACXB
RAM: 12 gb
HDD: Upgraded to 1tb SSD
Graphics: NVIDIA GeForce GT 735M with 2GB of video RAM

One suspicion I have: This sort of stutter is the kind of thing that I see when a program is suddenly and unexpectedly logging a bunch of extra data to a log file somewhere. Does Grimrock 2 have a dev/troubleshooting log file feature that I could look at, either to look at the logs to see if this is logging some kind of internal scripting errors, or to disable the logs to see if it solves the problem?

tfabris wrote:This, I have noticed, does not seem to be related to the graphics on the screen at the time. For example, sometimes I am cruising outdoors with a far draw distance and the frame rate is fine. Sometimes it is choppy. This is for the *same areas*. The same goes for when I am in a narrow dungeon corridor with very little on the screen and a very near draw distance. Sometimes the frame rate is fine, sometimes it is very choppy/stuttery.

This is a pretty good description of a system that's running stuff in the backgound causing heavy system load. Could be a virus scanner, a software update or other stuff requesting a lot of CPU time so LoG2 get's throttled.

Swap activity should not impact you since you got a lot of RAM plus an SSD.
Anyway if you run your system with active swap i'd switch that off.

It might be possible that your system randomly cuts the GPU's power due to heat build up but that's pure speculation.
You can check on that with a tool like GPU-Z by checking the temperature and perfcap sensors.

tfabris wrote: When the stuttering happens, sometimes if I wait it will just suddenly go away after a little while. Another thing that will make it go away is loading up a saved game.

Sounds a little bit like an memory problem: swapping or garbage collection. Petri optimized some time ago some problems with the LUA garbage collection (cleaning step could be related to what you experience) maybe with last patch a memory leak bug smuggled in, leading to excessive memory usage and therefore excessive swapping/garbage collection leading to stuttering? (What the memory load in this moments?)

Also, Grimrock seems to be also very heavy CPU wise (and for many setups CPU bound) ... can you relate this stuttering to an increased CPU load?

PS: in general grimrock is pretty ressource heavy, several problems are reported (over heating, not using all cores while starving CPU wise), mabye you can add your report also here or here

Dr.Disaster wrote:This is a pretty good description of a system that's running stuff in the backgound causing heavy system load.

Agreed, but I've looked at the windows task manager and there was nothing new there. ie., there isn't anything running during the bad times that there wasn't during the good times. Also, this system does not have third party virus scanner installed, it just uses the built-in Windows Defender that is built into windows 8.1. When I upgraded the system to an SSD, it was very recent, and it was a full wipe and re-install of Windows 8.1 to make sure it was completely clean. So I'm fairly certain there isn't anything else taking up CPU at the time besides Grimrock itself. (Unless Steam is doing something in the background at the time, since Steam is required for this to run?)

I agree, though, that such behavior is indicative of another program sapping CPU, so I will continue to investigate along these lines.

Out of interest: what's the brand and model of the SSD?

badhabit wrote:Sounds a little bit like an memory problem: swapping or garbage collection. Petri optimized some time ago some problems with the LUA garbage collection (cleaning step could be related to what you experience) maybe with last patch a memory leak bug smuggled in, leading to excessive memory usage and therefore excessive swapping/garbage collection leading to stuttering?

This is an interesting theory, and indeed, the issue I'm experiencing certainly fits that description. Is there an external way that I could examine and confirm whether this is the cause?

Also, Grimrock seems to be also very heavy CPU wise (and for many setups CPU bound) ... can you relate this stuttering to an increased CPU load?

I certainly notice the system's CPU cooling fan increasing its speed during the times that this happens. This is usually an indication of increased CPU load. Which would also be consistent with what I'm experiencing. The question is what's making it happen, and how do I find out.

tfabris wrote:

badhabit wrote:Sounds a little bit like an memory problem: swapping or garbage collection. Petri optimized some time ago some problems with the LUA garbage collection (cleaning step could be related to what you experience) maybe with last patch a memory leak bug smuggled in, leading to excessive memory usage and therefore excessive swapping/garbage collection leading to stuttering?

This is an interesting theory, and indeed, the issue I'm experiencing certainly fits that description. Is there an external way that I could examine and confirm whether this is the cause?

Also, Grimrock seems to be also very heavy CPU wise (and for many setups CPU bound) ... can you relate this stuttering to an increased CPU load?

I certainly notice the system's CPU cooling fan increasing its speed during the times that this happens. This is usually an indication of increased CPU load. Which would also be consistent with what I'm experiencing. The question is what's making it happen, and how do I find out.

Check CPU temperatures, CPU load (taskmanager under windows), check memory load, and specifically swap file usage. Is the memory usage continuously growing until the stuttering happens and the memory loads instantly drops (garbage collection) ?

Dr.Disaster wrote:Out of interest: what's the brand and model of the SSD?

It's a Samsung 840 EVO, 1tb. It cost me a pretty penny, but I got it because I killed the laptop's 1tb winchester hard drive. I killed it by accidentally dropping a guitar capo onto the laptop's keyboard while the system was up and running. It crashed the heads on the hard drive because the capo landed right on top of where the hard drive lived inside the laptop. I figured, that's it, no more winchester drives for me. SSD is the future.

I was aware of a performance problem with 840 EVO models, but they released a patch to fix it, and I've applied that patch.

badhabit wrote:Check CPU temperatures, CPU load (taskmanager under windows), check memory load, and specifically swap file usage. Is the memory usage continuously growing until the stuttering happens and the memory loads instantly drops (garbage collection) ?

Okay, I will investigate those things.

tfabris wrote:

Dr.Disaster wrote:Out of interest: what's the brand and model of the SSD?

It's a Samsung 840 EVO, 1tb. It cost me a pretty penny, but I got it because I killed the laptop's 1tb winchester hard drive. I killed it by accidentally dropping a guitar capo onto the laptop's keyboard while the system was up and running. It crashed the heads on the hard drive because the capo landed right on top of where the hard drive lived inside the laptop. I figured, that's it, no more winchester drives for me. SSD is the future.

I was aware of a performance problem with 840 EVO models, but they released a patch to fix it, and I've applied that patch.

I thought about some possible background process triggered SSD garbage collection thing going on, thus i asked.

Care to give us a quick info on general CPU and GPU temperatures, just to make sure it's not some heat issue you're looking at?