Re: CPU cores pinning with no NUMA on memory

[Narcis Garcia]

El 9/11/24 a les 4:05, Brett Neumeier ha escrit:
> On 11/8/24 1:04 PM, Narcis Garcia wrote:
> > Can be guest CPU/cores be pinned to host ones, without having to 
> > configure complicated mem/memdev parameters at qemu -numa parameter?
> >
> > I tried to run:
> > qemu-system-x86_64 -smp sockets=2,cores=2,threads=2 -numa node,cpus=0-5
> > but it complains about total memory for NUMA nodes (0x0) that should 
> > equal RAM size (qemu shows it already knows the size).
>
> On Linux, you can do this using taskset. Something like:
>
> taskset -c 0-5 qemu-system-x86_64 -smp sockets=2,cores=2,threads=2...
>
> will tell the scheduler to run the resulting qemu process only on the 
> first six cores. Does that help?

It seems so.
I've read CPU affinity is useful to reduce core/thread alternance 
overhead, and this way some guest processes could enhance performance.

My objective is guest has more host CPU time;
I currently see guest can be reporting 100% CPU usage while Qemu host is 
reporting 30% CPU usage, and this indicates to me hardware is not being 
used as it could.

--
Narcis Garcia