* [Qemu-devel] [question] Is there a plan to introduce a unified co-scheduling mechanism to CFS ?
@ 2014-10-10 11:37 Zhang Haoyu
2014-10-10 11:44 ` Wanpeng Li
0 siblings, 1 reply; 3+ messages in thread
From: Zhang Haoyu @ 2014-10-10 11:37 UTC (permalink / raw)
To: kvm, qemu-devel@nongnu.org Developers
Hi,
Is it worthy to introduce a unified co-scheduling mechanism to CFS ?
Because multiple cooperating threads or tasks frequently synchronize
with each other,
not executing them concurrently would only increase the latency of
synchronization.
For example, a thread blocking in spinlock to waiting for another thread
to release the same spinlock
might reduce its waiting time by being executed concurrently with the
thread which hold the same spinlock.
In virtualization scenario, multiple vcpus (which belong to the same vm)
co-scheduling is more desired
when several cooperating threads/task is running in guest.
Is there a plane for this work?
Thanks,
Zhang Haoyu
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [Qemu-devel] [question] Is there a plan to introduce a unified co-scheduling mechanism to CFS ?
2014-10-10 11:37 [Qemu-devel] [question] Is there a plan to introduce a unified co-scheduling mechanism to CFS ? Zhang Haoyu
@ 2014-10-10 11:44 ` Wanpeng Li
2014-10-10 12:00 ` Zhang Haoyu
0 siblings, 1 reply; 3+ messages in thread
From: Wanpeng Li @ 2014-10-10 11:44 UTC (permalink / raw)
To: Zhang Haoyu, kvm, qemu-devel@nongnu.org Developers
于 10/10/14, 7:37 PM, Zhang Haoyu 写道:
> Hi,
>
> Is it worthy to introduce a unified co-scheduling mechanism to CFS ?
> Because multiple cooperating threads or tasks frequently synchronize
> with each other,
> not executing them concurrently would only increase the latency of
> synchronization.
> For example, a thread blocking in spinlock to waiting for another
> thread to release the same spinlock
> might reduce its waiting time by being executed concurrently with the
> thread which hold the same spinlock.
> In virtualization scenario, multiple vcpus (which belong to the same
> vm) co-scheduling is more desired
> when several cooperating threads/task is running in guest.
>
> Is there a plane for this work?
Please refer to gang scheduler.
Regards,
Wanpeng Li
>
> Thanks,
> Zhang Haoyu
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^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [Qemu-devel] [question] Is there a plan to introduce a unified co-scheduling mechanism to CFS ?
2014-10-10 11:44 ` Wanpeng Li
@ 2014-10-10 12:00 ` Zhang Haoyu
0 siblings, 0 replies; 3+ messages in thread
From: Zhang Haoyu @ 2014-10-10 12:00 UTC (permalink / raw)
To: Wanpeng Li, kvm, qemu-devel@nongnu.org Developers
>> Hi,
>>
>> Is it worthy to introduce a unified co-scheduling mechanism to CFS ?
>> Because multiple cooperating threads or tasks frequently synchronize
with each other,
>> not executing them concurrently would only increase the latency of
synchronization.
>> For example, a thread blocking in spinlock to waiting for another
thread to release the same spinlock
>> might reduce its waiting time by being executed concurrently with
the thread which hold the same spinlock.
>> In virtualization scenario, multiple vcpus (which belong to the same
vm) co-scheduling is more desired
>> when several cooperating threads/task is running in guest.
>>
>> Is there a plane for this work?
>
> Please refer to gang scheduler.
>
Is there a mechanism to dynamically detect which vcpus belong to the
same gang?
Maybe a cooperative degree can be used to decide the threshold of which
vcpus belong to the same gang, just a wild thought.
> Regards,
> Wanpeng Li
>>
>> Thanks,
>> Zhang Haoyu
^ permalink raw reply [flat|nested] 3+ messages in thread
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2014-10-10 11:37 [Qemu-devel] [question] Is there a plan to introduce a unified co-scheduling mechanism to CFS ? Zhang Haoyu
2014-10-10 11:44 ` Wanpeng Li
2014-10-10 12:00 ` Zhang Haoyu
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