Re: [PATCH 0/8] RFC: vcpu pinning at qemu start

Glauber Costa
2008-03-05T13:13:06Z

Avi Kivity wrote:
> Glauber Costa wrote:
>> Hi guys,
>>
>> Here's a first series of patch aiming at vcpu pinning support in qemu.
>> Ideally, as vcpu as just normal threads, the usual userspace tools can
>> be used
>> to set cpu affinities mask.
>>
>> However, It makes it very difficult to _start_ a vm with vcpus pinned,
>> since
>> we don't know the thread ids from qemu in advance, nor do we know when
>> are the
>> vcpus created.
>>
>> The patches introduce a -cpu-map option, that, if specified, starts
>> the virtual cpus
>> with the specified affinities.
>>
>> Comments? Welcome. Random rants? Not welcome, but... how can I stop
>> you? So go ahead!
>>
>>
>
> A monitor interface would be more useful than a command line option, as
> it allows you to migrate the vcpus at runtime, and also control
> hotplugged cpus. For unmanaged use, taskset is probably sufficient to
> control affinity from the command line.
>
> Normally I encourage splitting patches, but this is a bit extreme. 1
> and 3 are pointless without each other, 4 and 5, 7 and 8. Hope that
> doesn't interfere with any pay-per-patch contract.
>
I'll post a new series that just expose the thread ids, so the
management tools can use plain taskset. As for the split, there's
nothing in my contract, but after all the x86 integration, it became a
mania for me. Ingo made me this way.