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Re: [PATCH v2 0/4] implement vcpu preempted check

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2016-07-06 18:44 GMT+08:00 Paolo Bonzini <pbonzini@redhat.com>:
>
>
> On 06/07/2016 08:52, Peter Zijlstra wrote:
>> On Tue, Jun 28, 2016 at 10:43:07AM -0400, Pan Xinhui wrote:
>>> change fomr v1:
>>>      a simplier definition of default vcpu_is_preempted
>>>      skip mahcine type check on ppc, and add config. remove dedicated macro.
>>>      add one patch to drop overload of rwsem_spin_on_owner and mutex_spin_on_owner.
>>>      add more comments
>>>      thanks boqun and Peter's suggestion.
>>>
>>> This patch set aims to fix lock holder preemption issues.
>>>
>>> test-case:
>>> perf record -a perf bench sched messaging -g 400 -p && perf report
>>>
>>> 18.09%  sched-messaging  [kernel.vmlinux]  [k] osq_lock
>>> 12.28%  sched-messaging  [kernel.vmlinux]  [k] rwsem_spin_on_owner
>>>  5.27%  sched-messaging  [kernel.vmlinux]  [k] mutex_unlock
>>>  3.89%  sched-messaging  [kernel.vmlinux]  [k] wait_consider_task
>>>  3.64%  sched-messaging  [kernel.vmlinux]  [k] _raw_write_lock_irq
>>>  3.41%  sched-messaging  [kernel.vmlinux]  [k] mutex_spin_on_owner.is
>>>  2.49%  sched-messaging  [kernel.vmlinux]  [k] system_call
>>>
>>> We introduce interface bool vcpu_is_preempted(int cpu) and use it in some spin
>>> loops of osq_lock, rwsem_spin_on_owner and mutex_spin_on_owner.
>>> These spin_on_onwer variant also cause rcu stall before we apply this patch set
>>>
>>
>> Paolo, could you help out with an (x86) KVM interface for this?
>
> If it's just for spin loops, you can check if the version field in the
> steal time structure has changed.

Steal time will not be updated until ahead of next vmentry except
wrmsr MSR_KVM_STEAL_TIME. So it can't represent it is preempted
currently, right?

Regards,
Wanpeng Li

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[PATCH v2 0/4] implement vcpu preempted check Pan Xinhui <xinhui.pan@linux.vnet.ibm.com> - 2016-06-28 12:50 +0200
  [PATCH v2 1/4] kernel/sched: introduce vcpu preempted check interface Pan Xinhui <xinhui.pan@linux.vnet.ibm.com> - 2016-06-28 12:50 +0200
  [PATCH v2 3/4] locking/osq: Drop the overload of osq_lock() Pan Xinhui <xinhui.pan@linux.vnet.ibm.com> - 2016-06-28 12:50 +0200
  [PATCH v2 2/4] powerpc/spinlock: support vcpu preempted check Pan Xinhui <xinhui.pan@linux.vnet.ibm.com> - 2016-06-28 12:50 +0200
    Re: [PATCH v2 2/4] powerpc/spinlock: support vcpu preempted check Wanpeng Li <kernellwp@gmail.com> - 2016-07-05 12:00 +0200
      Re: [PATCH v2 2/4] powerpc/spinlock: support vcpu preempted check xinhui <xinhui.pan@linux.vnet.ibm.com> - 2016-07-06 07:00 +0200
        Re: [PATCH v2 2/4] powerpc/spinlock: support vcpu preempted check Wanpeng Li <kernellwp@gmail.com> - 2016-07-06 08:50 +0200
          Re: [PATCH v2 2/4] powerpc/spinlock: support vcpu preempted check Peter Zijlstra <peterz@infradead.org> - 2016-07-06 10:00 +0200
            Re: [PATCH v2 2/4] powerpc/spinlock: support vcpu preempted check Wanpeng Li <kernellwp@gmail.com> - 2016-07-06 10:40 +0200
              Re: [PATCH v2 2/4] powerpc/spinlock: support vcpu preempted check xinhui <xinhui.pan@linux.vnet.ibm.com> - 2016-07-06 12:20 +0200
    Re: [PATCH v2 2/4] powerpc/spinlock: support vcpu preempted check Balbir Singh <bsingharora@gmail.com> - 2016-07-06 13:00 +0200
  [PATCH v2 4/4] kernel/locking: Drop the overload of {mutex,rwsem}_spin_on_owner Pan Xinhui <xinhui.pan@linux.vnet.ibm.com> - 2016-06-28 12:50 +0200
  Re: [PATCH v2 0/4] implement vcpu preempted check Peter Zijlstra <peterz@infradead.org> - 2016-07-06 09:00 +0200
    Re: [PATCH v2 0/4] implement vcpu preempted check Juergen Gross <jgross@suse.com> - 2016-07-06 09:50 +0200
      Re: [PATCH v2 0/4] implement vcpu preempted check Peter Zijlstra <peterz@infradead.org> - 2016-07-06 10:20 +0200
        Re: [PATCH v2 0/4] implement vcpu preempted check Juergen Gross <jgross@suse.com> - 2016-07-06 10:40 +0200
        Re: [PATCH v2 0/4] implement vcpu preempted check Paolo Bonzini <pbonzini@redhat.com> - 2016-07-06 14:50 +0200
        Re: [PATCH v2 0/4] implement vcpu preempted check Christian Borntraeger <borntraeger@de.ibm.com> - 2016-07-06 19:00 +0200
    Re: [PATCH v2 0/4] implement vcpu preempted check xinhui <xinhui.pan@linux.vnet.ibm.com> - 2016-07-06 12:10 +0200
    Re: [PATCH v2 0/4] implement vcpu preempted check Paolo Bonzini <pbonzini@redhat.com> - 2016-07-06 12:50 +0200
      Re: [PATCH v2 0/4] implement vcpu preempted check Wanpeng Li <kernellwp@gmail.com> - 2016-07-06 14:10 +0200
        Re: [PATCH v2 0/4] implement vcpu preempted check Paolo Bonzini <pbonzini@redhat.com> - 2016-07-06 14:40 +0200
          Re: [PATCH v2 0/4] implement vcpu preempted check Wanpeng Li <kernellwp@gmail.com> - 2016-07-06 15:10 +0200
          Re: [PATCH v2 0/4] implement vcpu preempted check Wanpeng Li <kernellwp@gmail.com> - 2016-07-07 10:50 +0200
            Re: [PATCH v2 0/4] implement vcpu preempted check Peter Zijlstra <peterz@infradead.org> - 2016-07-07 11:50 +0200
              Re: [PATCH v2 0/4] implement vcpu preempted check Wanpeng Li <kernellwp@gmail.com> - 2016-07-07 12:20 +0200
                Re: [PATCH v2 0/4] implement vcpu preempted check Wanpeng Li <kernellwp@gmail.com> - 2016-07-07 12:30 +0200
                Re: [PATCH v2 0/4] implement vcpu preempted check Peter Zijlstra <peterz@infradead.org> - 2016-07-07 13:20 +0200
                Re: [PATCH v2 0/4] implement vcpu preempted check Peter Zijlstra <peterz@infradead.org> - 2016-07-07 13:10 +0200
              Re: [PATCH v2 0/4] implement vcpu preempted check Peter Zijlstra <peterz@infradead.org> - 2016-07-07 13:10 +0200
              Re: [PATCH v2 0/4] implement vcpu preempted check Peter Zijlstra <peterz@infradead.org> - 2016-07-07 13:30 +0200
      Re: [PATCH v2 0/4] implement vcpu preempted check Peter Zijlstra <peterz@infradead.org> - 2016-07-06 14:10 +0200

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