| -----Original Message----- | From: kvm-ow...@vger.kernel.org [mailto:kvm-ow...@vger.kernel.org] On | Behalf Of Brian Jackson | Sent: Friday, April 20, 2012 8:01 AM | To: Stuart Yoder; Alexander Lyakas | Cc: kvm@vger.kernel.org | Subject: Re: Question about host CPU usage/allocation by KVM | | On Thu, 19 Apr 2012 13:01:54 -0500, Alexander Lyakas | <alex.bols...@gmail.com> wrote: | | > Hi Stuart, | > I have been doing some experiments, and I noticed that there are | > additional QEMU threads, besides the ones reported by "info cpus" | > command. In particular, the main QEMU thread (the one whose LWP is the | > same as its PID), also consumes significant CPU time. Is this | > expected? | | The extra threads are for various things. It can be for the vnc server if | you are using it. Threads are used to mimic aio in certain situations. | Etc. The main thread also does a lot of the device emulation work | (console, network, serial, block, etc.)
Is there some way to know what they are for ? or how many can get created ? I noticed that the number of threads go from ~4 to ~70 if I do some I/O inside the guest. Sunny | | | > | > Alex. | > | > | > On Wed, Apr 18, 2012 at 8:24 PM, Stuart Yoder <b08...@gmail.com> wrote: | >> On Tue, Apr 17, 2012 at 4:54 PM, Alexander Lyakas | >> <alex.bols...@gmail.com> wrote: | >>> Greetings everybody, | >>> | >>> Can anybody please point me to code/documentation regarding the | >>> following questions I have: | >>> | >>> - What does it actually mean using "-smp N" option, in terms of CPU | >>> sharing between the host and the guest? | >>> - How are guest CPUs mapped to host CPUs (if at all)? | >> | >> Each guest CPU (vcpu) corresponds to a QEMU thread. | >> You can see the thread ids in QEMU with "info cpus" in the QEMU | >> monitor. | >> | >> Since a vcpu is a thread you can apply standard Linux mechanisms to | >> managing those threads-- CPU affinity, etc. | >> | >> Stuart | > -- | > To unsubscribe from this list: send the line "unsubscribe kvm" in the | > body of a message to majord...@vger.kernel.org More majordomo info at | > http://vger.kernel.org/majordomo-info.html | -- | To unsubscribe from this list: send the line "unsubscribe kvm" in the body | of a message to majord...@vger.kernel.org More majordomo info at | http://vger.kernel.org/majordomo-info.html
