#PZ allocates only 8 processors on 12/24 thread CPU AMD 7900X3D

28 messages · Page 1 of 1 (latest)

fluid glade
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PZ should be able to allocate all available cores/threads of the CPU. In case of 7900X3D that is 12 cores or 24 threads.
Instead the console.txt states that only 8 processors are available.

Console.txt:

> OS: Linux, version: 6.2.9-200.fc37.x86_64, arch: amd64
> Available processors (cores): 8
> Memory free: 436.0 MB
> Memory max: 3072.0 MB
> Memory  total available to JVM: 488.0 MB
> /, Total: 1800.0 GB, Free: 1284.5781 GB
> ========================
version=41.78.16 demo=false```
AMD AM5 7900X3D is a specific processor with 6+6 configuration, where only one out of two CCDs (core clusters) have extra V-cache enabled. 
Allocating exactly 8 cores instead of 6 or 12 is unusual. 

lscpu:
```CPU(s):                  24
  On-line CPU(s) list:   0-23
Vendor ID:               AuthenticAMD
  Model name:            AMD Ryzen 9 7900X3D 12-Core Processor
    CPU family:          25
    Model:               97
    Thread(s) per core:  2
    Core(s) per socket:  12```
Steam:
```Processor Information:
    CPU Vendor:  AuthenticAMD
    CPU Brand:  AMD Ryzen 9 7900X3D 12-Core Processor          
    CPU Family:  0x19
    CPU Model:  0x61
    CPU Stepping:  0x2
    CPU Type:  0x0
    Speed:  5658 Mhz
    24 logical processors
    12 physical processors
    HyperThreading:  SupportedProcessor Information:
    CPU Vendor:  AuthenticAMD
    CPU Brand:  AMD Ryzen 9 7900X3D 12-Core Processor          
    CPU Family:  0x19
    CPU Model:  0x61
    CPU Stepping:  0x2
    CPU Type:  0x0
    Speed:  5658 Mhz
    24 logical processors
    12 physical processors
    HyperThreading:  Supported```
sour pike
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This would not be a PZ limitation, but more so an allocation limitation, perhaps coming from Linux or if you have any specific Bios settings just force pinning the V Cache cores to game applications

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Source: I have the same processor on Windows, it lists all cores correctly

fluid glade
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Thank you. Correctly meaning 12 or 24 (for reference)?

sour pike
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24, it counts the logical cores

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So I cannot really point to anything specific as to why PZ might only list 8, just that it would not be a PZ limitation

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I would probably not trust it fully and first check if htop or similar shows the core usage when the game loads

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If truly only 8 cores would be utilized then that would be a problem, if all are then maybe its just some other weird issue that should not affect performance

fluid glade
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I have installed PZ on my Windows drive (dual boot, same PC), and it correctly allocates 24 processors, according to console.txt.
My friend has Apple M1 with 8+2 configuration, and PZ also correctly allocates 10 processors.

So, something might be going on with PZ for Linux. Maybe PZ's JVM was compiled to only allocate max 8 cores.
Would need to have a confirmation from more Linux machines and CPU types.

sour pike
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Alright I did a test on my virtual machine

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LOG  : General     , 1681644699216> OS: Linux, version: 6.2.11-1-cachyos, arch: amd64
LOG  : General     , 1681644699217> Available processors (cores): 12
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So it only list physical cores, not the logical ones, at least on Linux it seems like

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Other than that, it lists them correctly for me

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Though lscpu only shows 12 as well

fluid glade
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My old machine is Xeon 4 cores 8 threads.
PZ reports 8 processors.

sour pike
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Therefore it may just be that VirtualBox doesnt support multithreading or something, I am not too familiar with virtual machines

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The fact is that Linux does in fact work with more cores

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The AMD processor is fairly new, so I am not sure of its implementation on Linux, perhaps it just pins certain processors to it depending on the application

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I am not sure what kind of optimizations work there

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Windows does a similar thing, just doesnt limit the processors to just specific ones being used

fluid glade
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AFAIK there is no specific optimisation present. All cores should be equal.
I am trying to determine whether this is a Linux specific bug or regression from standard 7xxx to v-cached 7xxxX3D processors.

sour pike
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I will try to dual boot Linux tomorrow on bare metal, since I do not fully trust a VM to be a good benchmark

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That could provide you with more info at least

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May also be distro specific but I very much doubt that, I generally use Arch since it should have the newest shiny things, just as the new Processor is, so it should have the best support for it (in theory)

fluid glade
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It is a possibility, but I consider it highly unlikely. I am using Fedora.
I will also try to get more info from our community and report back to this thread.
Thank you for your time and effort.

sour pike
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Done a test, it works just fine

fluid glade
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Great.
What CPU is this?