Re: [Xen-devel] [PATCH v6 10/11] x86, xen: support vcpu preempted check

[Pan Xinhui <xinhui@xxxxxxxxxxxxxxxxxx>]

在 2016/10/29 03:43, Konrad Rzeszutek Wilk 写道:
> On Fri, Oct 28, 2016 at 04:11:26AM -0400, Pan Xinhui wrote:
> > From: Juergen Gross <jgross@xxxxxxxx>
> >
> > Support the vcpu_is_preempted() functionality under Xen. This will
> > enhance lock performance on overcommitted hosts (more runnable vcpus
> > than physical cpus in the system) as doing busy waits for preempted
> > vcpus will hurt system performance far worse than early yielding.
> >
> > A quick test (4 vcpus on 1 physical cpu doing a parallel build job
> > with "make -j 8") reduced system time by about 5% with this patch.
> >
> > Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
> > Signed-off-by: Pan Xinhui <xinhui.pan@xxxxxxxxxxxxxxxxxx>
> > ---
> >  arch/x86/xen/spinlock.c | 3 ++-
> >  1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/arch/x86/xen/spinlock.c b/arch/x86/xen/spinlock.c
> > index 3d6e006..74756bb 100644
> > --- a/arch/x86/xen/spinlock.c
> > +++ b/arch/x86/xen/spinlock.c
> > @@ -114,7 +114,6 @@ void xen_uninit_lock_cpu(int cpu)
> >         per_cpu(irq_name, cpu) = NULL;
> >  }
> >
> > -
> Spurious change.
well, just remove one unnecessary blank line while at it.

> >  /*
> >   * Our init of PV spinlocks is split in two init functions due to us
> >   * using paravirt patching and jump labels patching and having to do
> > @@ -137,6 +136,8 @@ void __init xen_init_spinlocks(void)
> >         pv_lock_ops.queued_spin_unlock = 
> > PV_CALLEE_SAVE(__pv_queued_spin_unlock);
> >         pv_lock_ops.wait = xen_qlock_wait;
> >         pv_lock_ops.kick = xen_qlock_kick;
> > +
> > +       pv_lock_ops.vcpu_is_preempted = xen_vcpu_stolen;
> >  }
> >
> >  /*
> > --
> > 2.4.11
> >
> >
> > _______________________________________________
> > Xen-devel mailing list
> > Xen-devel@xxxxxxxxxxxxx
> > https://lists.xen.org/xen-devel

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