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-   -   Huge slowdown after 2 min in 3D games with >3GB RAM and Memory Remap Enabled (http://www.nvnews.net/vbulletin/showthread.php?t=127984)

miseiler 02-10-09 06:32 PM

Huge slowdown after 2 min in 32-bit games with 4+ GB RAM installed
 
1 Attachment(s)
Symptoms: You're in a game for a few minutes, then suddenly the FPS drops in half. It may happen on other 3D applications, I don't know. I don't run compiz or any other compositing manager.

It happens reproducibly every single time. In CS 1.6 there is further graphical corruption and eventually a crash.

The only solution I've found after trawling tons of bug reports is to disable Memory Remapping in the BIOS, which of course is only applicable if you have >3GB of RAM and a 64-bit linux distribution. When this is disabled, the problem disappears. Of course, so does all your RAM.

So far I've tested:
Kernels 2.6.27.1-28.4
Nvidia drivers 177.82-180.29

Enabling options like enable_mtrr_cleanup and nopat for the kernel don't change anything.

I don't even know if this is nvidia's fault. It certainly sounds like a kernel problem, but I don't know anything about anything.

miseiler 02-12-09 11:29 AM

Re: Huge slowdown after 2 min in 3D games with >3GB RAM and Memory Remap Enabled
 
Okay, I'm confused now.

I have 8GB of RAM in a 4x2GB configuration.

If I leave memory remapping on, and go down to 4GB of RAM, the problem disappears. I tested with different combinations of memory modules, but nothing changed. I also tested various RAM slots to make sure it wasn't that.

However, if I add a module (6GB), the problem comes back. If I go to 8 it fails, as I reported above.

The memory is fine; I've tested it using memtest86, the 'stress' program, raised/lowered voltage, relaxed timings/frequency, etc.

There aren't any heat problems. I have a lot of cooling. The ambient temperature never goes over 39C at worst.

I need 8GB of RAM to get any useful work done, and I want to play games (plus who knows what this is doing to my CUDA performance...) So I'm getting really frustrated. Anyone have any ideas?

zander 02-12-09 12:50 PM

Re: Huge slowdown after 2 min in 3D games with >3GB RAM and Memory Remap Enabled
 
Was the nvidia-bug-report.log file generated after the problem occurred? I'm not aware of fundamental problems with large memory configurations, they are not uncommon on Linux/x86-64 (a number of our customers use 16GB and 32GB configurations, for example).

miseiler 02-12-09 12:55 PM

Re: Huge slowdown after 2 min in 3D games with >3GB RAM and Memory Remap Enabled
 
Quote:

Originally Posted by zander (Post 1930887)
Was the nvidia-bug-report.log file generated after the problem occurred? I'm not aware of fundamental problems with large memory configurations, they are not uncommon on Linux/x86-64 (a number of our customers use 16GB and 32GB configurations, for example).

No...I booted up with 8GB enabled and generated a log. I'll post a bug report after a slowdown or crash when I get home from work.

One thing though.. If I stop the 3D application (CS 1.6), and then restart, I get another 2 min before the slowdown/corruption occurs.

miseiler 02-12-09 04:09 PM

Re: Huge slowdown after 2 min in 3D games with >3GB RAM and Memory Remap Enabled
 
1 Attachment(s)
Better yet, this log was created while the FPS drop and graphical corruption occurred.

Thank you for your assistance.

zander 02-12-09 04:40 PM

Re: Huge slowdown after 2 min in 3D games with >3GB RAM and Memory Remap Enabled
 
Unfortunately, I don't see anything that would explain the slowdown you're seeing (no driver error messages, etc.). The nature of the symptoms observed suggests a system-level problem of some kind. Is your power supply adequate for the system configuration?

hansen 02-12-09 04:47 PM

Re: Huge slowdown after 2 min in 3D games with >3GB RAM and Memory Remap Enabled
 
I am experiencing exactly the same problem on my Linux x86-64 Box (AMD CPU).
Happened since I've upgraded the RAM from 3GB to 8GB, and therefor had to compile the GART IOMMU into the kernel.
When playing a 3D game (in my case 'ET') it first runs fine for a few minutes, but then chokes down. I did watch the processes and the game is constantly leaking huge amounts of memory.

I then tried the various driver versions back to 173.14.12, and with every newer driver the memory leak got worse. Also to note is, that the game starts to choke when the leaking process reaches around 4GB of memory. I can kill the process and anything is fine again.

I spend the last whole two months with trying to find an issue in my systeminstallation/configuration
and even tried various kernel commandline options in regard to that...
but the only temporary reasonable solution I've found is to pass mem=3G to the kernel command line. And the process behaves like it should (stays all the time at nearly same memory amounts).
Obvisiously with the parameter set, the hole GART IOMMU thingie doesn't get loaded. And there is only the SWIOTLB and AGPGART which depends on that. So maybe you know where to look at...

That means for me, I have to reboot my box and interactively add this parameter to grub when I want to play a game, since I don't want to go without all the RAM all the time.
And besides that, there are no other problems here (like that corruption thingie).

hansen 02-12-09 04:49 PM

Re: Huge slowdown after 2 min in 3D games with >3GB RAM and Memory Remap Enabled
 
Hello, nice to know I am not alone! :D

I am experiencing exactly the same problem on my Linux x86-64 Box (AMD CPU).
Happened since I've upgraded the RAM from 3GB to 8GB, and therefor had to compile the GART IOMMU into the kernel.
When playing a 3D game (in my case 'ET') it first runs fine for a few minutes, but then chokes down. I did watch the processes and the game is constantly leaking huge amounts of memory.

I then tried the various driver versions back to 173.14.12, and with every newer driver the memory leak got worse. Also to note is, that the game starts to choke when the leaking process reaches around 4GB of memory. I can kill the process and anything is fine again.

I spend the last whole two months with trying to find an issue in my systeminstallation/configuration
and even tried various kernel commandline options in regard to that...
but the only temporary reasonable solution I've found is to pass mem=3G to the kernel command line. And the process behaves like it should (stays all the time at nearly same memory amounts).
Obvisiously with the parameter set, the hole GART IOMMU thingie doesn't get loaded. And there is only the SWIOTLB and AGPGART which depends on that. So maybe you know where to look at...

That means for me, I have to reboot my box and interactively add this parameter to grub when I want to play a game, since I don't want to go without all the RAM all the time.
And besides that, there are no other problems here (like that corruption thingie).

Bye

miseiler 02-12-09 05:41 PM

Re: Huge slowdown after 2 min in 3D games with >3GB RAM and Memory Remap Enabled
 
Looking at my bug report, I don't have that kind of leak (4GB). However, 1.8GB used for wine is troubling.

I will check memory usage when the program is working correctly to see if there is a difference.

miseiler 02-12-09 10:25 PM

Re: Huge slowdown after 2 min in 3D games with >3GB RAM and Memory Remap Enabled
 
EDIT: I can replicate a memory leak using 32-bit apps, see further in the thread

miseiler 02-13-09 09:24 AM

Re: Huge slowdown after 2 min in 3D games with >3GB RAM and Memory Remap Enabled
 
Another odd/interesting thing about this problem is with drivers prior to 180.x, it takes a LOT longer to happen. I can usually play an entire map or two before it goes wrong.

gbil 02-13-09 11:18 AM

Re: Huge slowdown after 2 min in 3D games with >3GB RAM and Memory Remap Enabled
 
Quote:

Originally Posted by miseiler (Post 1931211)
Looking at my bug report, I don't have that kind of leak (4GB). However, 1.8GB used for wine is troubling.

I will check memory usage when the program is working correctly to see if there is a difference.

Wine has a known problem with lots of RAM in 64bit kernels.

Do a search in the forum and you will find it.


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