There were a few reports of difficulties with pinning threads to CPU cores on Windows systems with more than 64 logical cores.
One reported at Discord, another two days ago at Discord
Logs look something like this:
2024-03-21T21:38:31.921825Z INFO subspace_farmer::commands::farm: Multiple L3 cache groups detected l3_cache_groups=4
2024-03-21T21:38:31.927377Z WARN subspace_farmer::utils: Failed to pin thread to CPU cores error=hwloc_set_thread_cpubind failed with errno None cpu_cores=CpuSet(28-41)
2024-03-21T21:38:31.927954Z WARN subspace_farmer::utils: Failed to pin thread to CPU cores error=hwloc_set_thread_cpubind failed with errno None cpu_cores=CpuSet(28-41)
2024-03-21T21:38:31.929041Z WARN subspace_farmer::utils: Failed to pin thread to CPU cores error=hwloc_set_thread_cpubind failed with errno None cpu_cores=CpuSet(28-41)
2024-03-21T21:38:31.929118Z WARN subspace_farmer::utils: Failed to pin thread to CPU cores error=hwloc_set_thread_cpubind failed with errno None cpu_cores=CpuSet(42-55)
2024-03-21T21:38:31.929317Z WARN subspace_farmer::utils: Failed to pin thread to CPU cores error=hwloc_set_thread_cpubind failed with errno None cpu_cores=CpuSet(28-41)
According to Processor Groups - Win32 apps | Microsoft Learn this should no longer be an issue on Windows 11/Windows Server 2022.
So I tried to reproduce it in Windows 11 VM with 2 NUMA nodes with 28 cores/56 logical threads each on Windows 11 Pro 23H2 22631.3296 and wasn’t able to. Core pinning seems to work fine without warnings, I see all 112 logical cores utilized:
So I’m looking for ways to reproduce this issue if it still exists in practice.