Ubuntu in WSL2 only sees 12 of 16 cores of 12th Gen Intel CPU

[liuzheng-arctic]

Version

Microsoft Windows [Version 10.0.22621.1105]

WSL Version

• WSL 2
• WSL 1

Kernel Version

Linux version 5.15.79.1-microsoft-standard-WSL2

Distro Version

Ubuntu 22.04

Other Software

OpenMPI can only use 12 cores that is available in WSL2, out of the total 16.

Repro Steps

Run lscpu from terminal

Expected Behavior

Return 16 cores and 24 thread for the Intel 12800HX CPU, as is listed in the specs:
https://www.intel.com/content/www/us/en/products/sku/226058/intel-core-i712800hx-processor-25m-cache-up-to-4-80-ghz/specifications.html

Actual Behavior

Architecture: x86_64
CPU op-mode(s): 32-bit, 64-bit
Address sizes: 39 bits physical, 48 bits virtual
Byte Order: Little Endian
CPU(s): 24
On-line CPU(s) list: 0-23
Vendor ID: GenuineIntel
Model name: 12th Gen Intel(R) Core(TM) i7-12800HX
CPU family: 6
Model: 151
Thread(s) per core: 2
Core(s) per socket: 12
Socket(s): 1
Stepping: 2
BogoMIPS: 4608.01
Flags: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse ss e2 ss ht syscall nx pdpe1gb rdtscp lm constant_tsc rep_good nopl xtopology tsc_reliable nonstop _tsc cpuid pni pclmulqdq vmx ssse3 fma cx16 pcid sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline _timer aes xsave avx f16c rdrand hypervisor lahf_lm abm 3dnowprefetch invpcid_single ssbd ibrs
ibpb stibp ibrs_enhanced tpr_shadow vnmi ept vpid ept_ad fsgsbase tsc_adjust bmi1 avx2 smep bmi 2 erms invpcid rdseed adx smap clflushopt clwb sha_ni xsaveopt xsavec xgetbv1 xsaves avx_vnni(base) zliu@DESKTOP-5L16Q37:~$
ili ties
Virtualization features:
Virtualization: VT-x
Hypervisor vendor: Microsoft
Virtualization type: full
Caches (sum of all):
L1d: 576 KiB (12 instances)
L1i: 384 KiB (12 instances)
L2: 15 MiB (12 instances)
L3: 25 MiB (1 instance)
Vulnerabilities:
Itlb multihit: Not affected
L1tf: Not affected
Mds: Not affected
Meltdown: Not affected
Mmio stale data: Not affected
Retbleed: Mitigation; Enhanced IBRS
Spec store bypass: Mitigation; Speculative Store Bypass disabled via prctl and seccomp
Spectre v1: Mitigation; usercopy/swapgs barriers and __user pointer sanitization
Spectre v2: Mitigation; Enhanced IBRS, IBPB conditional, RSB filling, PBRSB-eIBRS SW sequence
Srbds: Not affected
Tsx async abort: Not affected

Diagnostic Logs

I used a Ubuntu 22.04 usb boot drive for this test and found the correct number of cores. So it is not a Ubuntu issue.
It does not seems to be due to WSL limiting the number of cores available because it recognizes all the 24 threads. This may not necessarily affect the performance but it is really confusing.

[ducktapeonmydesk]

I am having the same issue.

Running an Intel Core i9-13950HX with 24 cores and 32 threads, but WSL2 only sees 16 cores.

[LiYijin]

I met the same problem.
I am confusing the 12 core is P core or E core?

[microsoft-github-policy-service]

This issue has been automatically closed since it has not had any activity for the past year. If you're still experiencing this issue please re-file this as a new issue or feature request.

Thank you!