exact pin vcore to physical core

[efeu]

While running low latency tasks in VMs, you may want to pin your vcores to physical cores to not loose caches and avoid moving tasks to cores which are running on lower frequency first when moving to them.

The existing pve_helper scripts managed to pin the qemu CPU threads to a "CPU pool", while this will keep you lvl3 cache, but not lvl1/2.

I see a lot of threads here and on Reddit where ppl ask how to do this on proxmox, like it is possible with libvirt.

I wrote a little script for my VM for a 16/32 CPU. Feel free to modify and use it on your own.

To do so you have to reenable croups v1 (dunno if this has any negative effect)

It's quick and dirty, so first modify it for your usecase

https://github.com/efschu/proxmox_cpupin

 

[LnxBil]

If you do such hardcore devirtualization, I'd also recommend using hugepages to get an additional good 10% more memory allocation performance. And of course enable NUMA-awareness.

 

[efeu]

If you do such hardcore devirtualization, I'd also recommend using hugepages to get an additional good 10% more memory allocation performance. And of course enable NUMA-awareness.

Sure, (but) this is already built into proxmox.
CPU pinning is not

 

[LnxBil]

CPU pinning is not

Of course not and it most probably never will. Just too specific.

The cset stuff is really cool and for others trying to understand, this is very useful in understanding.