Re: [Qemu-devel] multiprocessor on kvm

2011-11-08 Thread 陳韋任
> I am wondering when using -smp 16 and --enable-kvm at the same time > (while the host has 4 cores), what will happen? "-smp 16" will lauch 16 virtual cpu threads, and "--enable-kvm" means you run those threads on physical cpus *at the same time*. How 16 virtual cpu threads are scheduled on 4 p

Re: [Qemu-devel] multiprocessor on kvm

2011-11-08 Thread Dong Xu Wang
I am wondering when using -smp 16 and --enable-kvm at the same time (while the host has 4 cores), what will happen? 在 2011年11月8日 下午9:08,陳韋任 写道: >> so qemu exposes multiple processors to the guest os by having multiple >> vCPUs. and it realizes the multiple vCPUs by either using RR on a >> single

Re: [Qemu-devel] multiprocessor on kvm

2011-11-08 Thread Xin Tong
now question is if one of the cpu vmexits the guest due to trapping instruction ( i.e. PIO), the host linux will have only one physical cpu to run on as the other cpus are still running the guest os ? Am I right ? Thanks Xin 2011/11/8 Xin Tong : > so qemu exposes multiple processors to the gues

Re: [Qemu-devel] multiprocessor on kvm

2011-11-08 Thread 陳韋任
> so qemu exposes multiple processors to the guest os by having multiple > vCPUs. and it realizes the multiple vCPUs by either using RR on a > single host cpu (qemu ) or using multiple host cpus (kvm). yes. Regards, chenwj -- Wei-Ren Chen (陳韋任) Computer Systems Lab, Institute of Information S

Re: [Qemu-devel] multiprocessor on kvm

2011-11-08 Thread Xin Tong
so qemu exposes multiple processors to the guest os by having multiple vCPUs. and it realizes the multiple vCPUs by either using RR on a single host cpu (qemu ) or using multiple host cpus (kvm). Thanks Xin 2011/11/8 Stefan Hajnoczi : > On Tue, Nov 8, 2011 at 12:10 PM, 陳韋任 wrote: >> On Tue, No

Re: [Qemu-devel] multiprocessor on kvm

2011-11-08 Thread Stefan Hajnoczi
On Tue, Nov 8, 2011 at 12:10 PM, 陳韋任 wrote: > On Tue, Nov 08, 2011 at 08:04:44PM +0800, 陳韋任 wrote: >> > I am wondering that when one uses qemu with kvm. How many cores are >> > exposed and available to the guest os ( assuming the host has 4 cores >> > ). is this configurable ? >> >> QEMU provide

Re: [Qemu-devel] multiprocessor on kvm

2011-11-08 Thread 陳韋任
On Tue, Nov 08, 2011 at 08:04:44PM +0800, 陳韋任 wrote: > > I am wondering that when one uses qemu with kvm. How many cores are > > exposed and available to the guest os ( assuming the host has 4 cores > > ). is this configurable ? > > QEMU provides "-smp" option, but those virtual cpus are schedul

Re: [Qemu-devel] multiprocessor on kvm

2011-11-08 Thread 陳韋任
> I am wondering that when one uses qemu with kvm. How many cores are > exposed and available to the guest os ( assuming the host has 4 cores > ). is this configurable ? QEMU provides "-smp" option, but those virtual cpus are scheduled in round-robin fashion. In other words, it's not real parall

[Qemu-devel] multiprocessor on kvm

2011-11-08 Thread Xin Tong
I am wondering that when one uses qemu with kvm. How many cores are exposed and available to the guest os ( assuming the host has 4 cores ). is this configurable ? Thanks Xin