Re: [Qemu-devel] Enabling Hyperthreading for Guest

[Erik Rull <erik.rull@rdsoftware.de>]

Alex Williamson wrote:
> See the extended -smp options:
>
> -smp n[,maxcpus=cpus][,cores=cores][,threads=threads][,sockets=sockets]
>                  set the number of CPUs to 'n' [default=1]
>                  maxcpus= maximum number of total cpus, including
>                  offline CPUs for hotplug, etc
>                  cores= number of CPU cores on one socket
>                  threads= number of threads on one CPU core
>                  sockets= number of discrete sockets in the system
>
> Try something like:
>
> -smp 4,cores=2,threads=2,sockets=1
>
> Alex
>

Great - the correct combination made it :-)

But the SMP-Performance-Benchmark is horrible :-(
"Only" between 0.35 and 1.05 for the above combination.
I have the same architecture on the host (2 cores w/ ht enabled) so there 
are enough real cores available for computation.

Any idea what could slow down the performance here?

Best regards,

Erik