On Fri, Oct 28, 2016 at 04:11:26AM -0400, Pan Xinhui wrote: > From: Juergen Gross <jgr...@suse.com> > > 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 <jgr...@suse.com> > Signed-off-by: Pan Xinhui <xinhui....@linux.vnet.ibm.com> > --- > 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. > /* > * 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-de...@lists.xen.org > https://lists.xen.org/xen-devel
