[SOLVED] Maybe issue with swap and the 6.6 kernel?

garpu · 12-31-2023, 10:42 AM

Slackware64-current with multilib, nvidia 545.29.02, 16GB RAM, Geforce 1050ti, Ryzen 5 1600. (6.6.8 huge kernel with preempt=full) Everything is patched as of last night.

I've noticed that when my computer is under a heavy load (like while playing Guild Wars 2 via proton and DXVK) that while I'll have at least 7GB buff/cache and 7GB available memory (as reported to top), my swap usage will go up. (Performance doesn't seem to be affected any, and I can quit the application, and the number will slowly go down. I can clear the swap with swapoff/swapon.) With the holidays, I haven't had as much time to game, but I was having similar issues with Diablo IV. (Also with proton, but with VKD3D, and also does have an nvidia-based memory leak that's affecting windows.)

The gamingonlinux people didn't think this was too much of an issue, because swap does get used, and I'm probably not noticing it, because most people don't obsessively watch top while they do other things. My partner says this is just a bug, and it's probably not a problem, either.

There's nothing in dmesg, messages, or syslog to indicate any OOM errors. I probably wouldn't notice it, if I didn't randomly check top.

No issues with supercollider, playing videos, or just non-gaming usage. I can play Vampire Survivors and watch youtube videos, and no problems with RAM.

Boot strings: "root=/dev/sda2 vga=normal ro pti=off rcu_nocbs=0-11 threadirqs preempt=full"

So did something change with memory usage and the 6.6 kernel that I'm noticing? Is this a kernel bug? vulkan bug? Buggy software (gw2 and diablo IV)? Not a bug at all?

Petri Kaukasoina · 12-31-2023, 10:58 AM

How much does it use swap? How large swap do you have?

garpu · 12-31-2023, 11:07 AM

I don't think I"ve seen the swap go above 1GB. I've got 16GB swap.

Petri Kaukasoina · 12-31-2023, 11:53 AM

At the moment when the swap use is high, do you have lots of usage in tmpfs?

Code:

df -t tmpfs

If the game puts lots of stuff there, they are in RAM, but unneeded pages go out to swap.

garpu · 12-31-2023, 02:12 PM

Code:

Filesystem     1K-blocks   Used Available Use% Mounted on
tmpfs              32768   1504     31264   5% /run
tmpfs            8152476 682688   7469788   9% /dev/shm
cgroup_root         8192      0      8192   0% /sys/fs/cgroup
tmpfs            1630492     12   1630480   1% /run/user/1000

Nothing exceptionally note-worthy. Bug report it with proton?

Or this? https://github.com/doitsujin/dxvk/issues/958

garpu · 12-31-2023, 02:24 PM

Code:

MiB Mem :  15922.8 total,    244.1 free,   7603.3 used,   8075.4 buff/cache
MiB Swap:  16384.0 total,  15762.4 free,    621.6 used.   7296.9 avail Mem 

  PID USER      PR  NI    VIRT    RES    SHR S  %CPU  %MEM     TIME+ COMMAND    
32046 hildega+  25   5   40.1g   3.5g 315692 S 515.1  22.7  12:10.18 Gw2-64.exe

Was able to make the swap go up by loading into different areas.

Code:

---------------------------------------------------------------------------------------+
| NVIDIA-SMI 545.29.02              Driver Version: 545.29.02    CUDA Version: 12.3     |
|-----------------------------------------+----------------------+----------------------+
| GPU  Name                 Persistence-M | Bus-Id        Disp.A | Volatile Uncorr. ECC |
| Fan  Temp   Perf          Pwr:Usage/Cap |         Memory-Usage | GPU-Util  Compute M. |
|                                         |                      |               MIG M. |
|=========================================+======================+======================|
|   0  NVIDIA GeForce GTX 1050 Ti     Off | 00000000:07:00.0  On |                  N/A |
| 35%   54C    P0              N/A /  75W |   3587MiB /  4096MiB |     43%      Default |
|                                         |                      |                  N/A |
+-----------------------------------------+----------------------+----------------------+
                                                                                         
+---------------------------------------------------------------------------------------+
| Processes:                                                                            |
|  GPU   GI   CI        PID   Type   Process name                            GPU Memory |
|        ID   ID                                                             Usage      |
|=======================================================================================|
|    0   N/A  N/A       407      G   /home/hildegard/bin/firefox/firefox           3MiB |
|    0   N/A  N/A       816      G   ...,WinRetrieveSuggestionsOnlyOnDemand       40MiB |
|    0   N/A  N/A      1286      G   ...local/share/Steam/ubuntu12_32/steam        1MiB |
|    0   N/A  N/A      1292      G   ...re/Steam/ubuntu12_64/steamwebhelper        5MiB |
|    0   N/A  N/A     32046    C+G   ...apps\common\Guild Wars 2\Gw2-64.exe     2745MiB |
|    0   N/A  N/A     32111    C+G   ...\Guild Wars 2\bin64\cef\CefHost.exe      549MiB |
|    0   N/A  N/A     32489      G   /usr/libexec/Xorg                           229MiB |
|    0   N/A  N/A     32540      G   xfwm4                                         1MiB |
|    0   N/A  N/A     32641      G   kalendarac                                    1MiB |
+---------------------------------------------------------------------------------------+

I thought VRAM doesn't use swap, though? It seems to happen when my VRAM approaches the limit.

garpu · 01-02-2024, 05:36 PM

Tentatively marking this one solved, because I don't think it's a Slackware problem, and I think it's a Steam problem, since I only see it with dxvk games.

Aeterna · 01-04-2024, 09:04 AM

You can always play with VM parameters. These can improve overall performance:
vm.vfs_cache_pressure = 50
vm.swappiness = 10
vm.dirty_background_ratio = 10
vm.dirty_background_bytes = 0
vm.dirty_ratio = 20
vm.dirty_bytes = 0
vm.dirty_writeback_centisecs = 3000
vm.dirty_expire_centisecs = 500

These are examples to tweak. Once tuned, probably will improve system responsiveness (not for server). The ratio variant will become 0 if we set the bytes variant, and vice versa.

Setting general preempt_full may not be enough for specific task.
I don't have Slackware kernel, but CONFIG_KPROBE_EVENTS=y disables preempt.
https://stackoverflow.com/questions/...to-reenable-it

garpu · 01-06-2024, 08:19 AM

Thanks, Aeterna! Will give it a try once I'm not on cold meds.

ETA: tweaking the swapiness did fix it, I think! Haven't had the brainpower to really do much more than watch youtube videos, though.