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Groups > linux.kernel > #1576998

Re: [PATCH 2/2] locking/mutex,rwsem: Reduce vcpu_is_preempted() calling frequency

From Peter Zijlstra <peterz@infradead.org>
Newsgroups linux.kernel
Subject Re: [PATCH 2/2] locking/mutex,rwsem: Reduce vcpu_is_preempted() calling frequency
Date 2017-02-08 21:00 +0100
Message-ID <t8FWA-4iE-83@gated-at.bofh.it> (permalink)
References <t8EQO-3Ed-13@gated-at.bofh.it> <t8EQO-3Ed-23@gated-at.bofh.it>
Organization linux.* mail to news gateway

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On Wed, Feb 08, 2017 at 01:00:25PM -0500, Waiman Long wrote:
> As the vcpu_is_preempted() call is pretty costly compared with other
> checks within mutex_spin_on_owner() and rwsem_spin_on_owner(), they
> are done at a reduce frequency of once every 256 iterations.

That's just disgusting.

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Thread

[PATCH 1/2] x86/paravirt: Don't make vcpu_is_preempted() a callee-save function Waiman Long <longman@redhat.com> - 2017-02-08 19:10 +0100
  [PATCH 2/2] locking/mutex,rwsem: Reduce vcpu_is_preempted() calling frequency Waiman Long <longman@redhat.com> - 2017-02-08 19:10 +0100
    Re: [PATCH 2/2] locking/mutex,rwsem: Reduce vcpu_is_preempted()  calling frequency Waiman Long <longman@redhat.com> - 2017-02-08 20:20 +0100
    Re: [PATCH 2/2] locking/mutex,rwsem: Reduce vcpu_is_preempted()  calling frequency Peter Zijlstra <peterz@infradead.org> - 2017-02-08 21:00 +0100
  Re: [PATCH 1/2] x86/paravirt: Don't make vcpu_is_preempted() a  callee-save function Peter Zijlstra <peterz@infradead.org> - 2017-02-08 20:20 +0100
    Re: [PATCH 1/2] x86/paravirt: Don't make vcpu_is_preempted() a  callee-save function Waiman Long <longman@redhat.com> - 2017-02-08 21:50 +0100

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