[vfio-users] Optimize vm and host performance, is dual xeon the way ?

[thibaut noah]

So is this the right emulation? If i understand correctly what i'm trying
to get is a 3cores with 2threads per core ? (so 6cores pinned?)
I don't have that much knowledge in cpu so i'm kinda lost here.

<cputune>
    <vcpupin vcpu='0' cpuset='1'/>
    <vcpupin vcpu='1' cpuset='2'/>
    <vcpupin vcpu='2' cpuset='3'/>
    <vcpupin vcpu='3' cpuset='5'/>
    <vcpupin vcpu='4' cpuset='6'/>
    <vcpupin vcpu='5' cpuset='7'/>
  </cputune>

2015-12-26 18:53 GMT+01:00 Karsten Elfenbein <karsten.elfenbein at gmail.com>:

> check that the 2 cores for the host OS are on the same physical core
> and that the VM does not use those 2 processors with the same core id
>
> cat /proc/cpuinfo | grep -e processor -e 'core id'
>
> CPU 0-3 should be the core 0-3
> CPU 4-7 should be the core 0-3 again with HT
>
> so leaving out CPU 0 and 4 should keep core 0 idle and the host OS
> responsive
>
> taskset 1-3,5-7 startVM.sh
>
> Karsten
>
> 2015-12-26 12:56 GMT+01:00 Eddie Yen <missile0407 at gmail.com>:
> > Pining CPU can reduce the happening that host and guest using the same
> > thread at the same time.
> >
> > And I don't know which program you're using on Fedora, so I don't have
> quite
> > answer that 2 threads is enough for host or not.
> > It's all depends on your usage case.
> >
> > 2015-12-26 19:44 GMT+08:00 thibaut noah <thibaut.noah at gmail.com>:
> >>
> >> My cpu is a i7 4790k, is pinning the cpu usefull ? I'll try to derp a
> bit
> >> with the vcpu thing, just afraid 2 threads aren't enough for fedora :/
> >>
> >> 2015-12-26 11:59 GMT+01:00 Eddie Yen <missile0407 at gmail.com>:
> >>>
> >>> I forgot your CPU type, so I don't know about your case.
> >>>
> >>> But, as I'm using 4820K, I usually using 4 to 6 threads gave to VM,
> only
> >>> use 2 threads for Fedora host.
> >>> And most important is vCPU tweaks, especially CPU topology and Hyper-V.
> >>>
> >>> For me, I usually set topology as "sockets=1 cores=6 threads=1" if
> using
> >>> 6 threads from host.
> >>> Then set cpuset= to let vCPU worked on pointed CPU threads.
> >>>
> >>> IME, set all threads as vCPU cores can got better performance on
> Windows
> >>> 10.
> >>>
> >>> 2015-12-26 18:00 GMT+08:00 thibaut noah <thibaut.noah at gmail.com>:
> >>>>
> >>>> Hello guys merry christmas ! o/
> >>>> My current issue is vm and host optimization, i use my windows 10 vm
> for
> >>>> gaming purposes only (like most of us i think), problem is, to keep my
> >>>> performances on windows high i drain too much ressources on my fedora
> host
> >>>> thus making it almost useless (also when leaving the vm i most of the
> time
> >>>> found myself unable to use fedora at all so i have to reboot...).
> >>>> So is it possible to improve performances to the max on the guest
> >>>> without almost killing the host ?
> >>>> Should i consider switching my gear for a bi-xeon? (to assign one
> fully
> >>>> to the host and one to the guest)
> >>>> I'm actually not sure about what happen here, does anyone ran into the
> >>>> same sort of issue?
> >>>> Have a good day
> >>>>
> >>>> _______________________________________________
> >>>> vfio-users mailing list
> >>>> vfio-users at redhat.com
> >>>> https://www.redhat.com/mailman/listinfo/vfio-users
> >>>>
> >>>
> >>
> >
> >
> > _______________________________________________
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> > vfio-users at redhat.com
> > https://www.redhat.com/mailman/listinfo/vfio-users
> >
>
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