On Wed, May 23, 2012 at 3:54 PM, Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote: > On Wed, 2012-05-23 at 14:32 +0800, Liu Ping Fan wrote: >> From: Liu Ping Fan <pingfank@xxxxxxxxxxxxxxxxxx> >> >> The guest's scheduler can not see the numa info on the host and >> this will result to the following scene: >> Supposing vcpu-a on nodeA, vcpu-b on nodeB, when load balance, >> the tasks' pull and push between these vcpus will cost more. But >> unfortunately, currently, the guest is just blind to this. >> >> This patch want to export the host numa info to the guest, and help >> guest to rebuild its sched domain based on host's info. > > Hell no, we're not going to export sched domains, if kvm/qemu wants this > its all in sysfs. > > The whole sched_domain stuff is a big enough pain as it is, exporting > this and making it a sodding API is the worst thing ever. > > Whatever brainfart made you think this is needed anyway? sysfs contains > the host topology, qemu can already create whatever guest topology you > want (see the -smp and -numa arguments), so what gives? I think -numa option will be used to emulate the special virtual machine to customer, and do not necessary map to host topology. And even we map them exactly with -numa option, the movement of vcpu threads among host nodes will break the topology initialized by -numa option. So give the guest a opportunity to adjust its topology? Thanks and regards, pingfan -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
