Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S942326AbcJ1Tpg (ORCPT ); Fri, 28 Oct 2016 15:45:36 -0400 Received: from aserp1040.oracle.com ([141.146.126.69]:27336 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934958AbcJ1Tpe (ORCPT ); Fri, 28 Oct 2016 15:45:34 -0400 Date: Fri, 28 Oct 2016 15:43:25 -0400 From: Konrad Rzeszutek Wilk To: Pan Xinhui Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, virtualization@lists.linux-foundation.org, linux-s390@vger.kernel.org, xen-devel-request@lists.xenproject.org, kvm@vger.kernel.org, xen-devel@lists.xenproject.org, x86@kernel.org, kernellwp@gmail.com, jgross@suse.com, David.Laight@ACULAB.COM, rkrcmar@redhat.com, peterz@infradead.org, benh@kernel.crashing.org, bsingharora@gmail.com, will.deacon@arm.com, borntraeger@de.ibm.com, mingo@redhat.com, paulus@samba.org, mpe@ellerman.id.au, pbonzini@redhat.com, paulmck@linux.vnet.ibm.com, boqun.feng@gmail.com Subject: Re: [Xen-devel] [PATCH v6 10/11] x86, xen: support vcpu preempted check Message-ID: <20161028194325.GE2879@char.us.oracle.com> References: <1477642287-24104-1-git-send-email-xinhui.pan@linux.vnet.ibm.com> <1477642287-24104-11-git-send-email-xinhui.pan@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1477642287-24104-11-git-send-email-xinhui.pan@linux.vnet.ibm.com> User-Agent: Mutt/1.6.2 (2016-07-01) X-Source-IP: userv0021.oracle.com [156.151.31.71] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1604 Lines: 48 On Fri, Oct 28, 2016 at 04:11:26AM -0400, Pan Xinhui wrote: > From: Juergen Gross > > 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 > Signed-off-by: Pan Xinhui > --- > 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-devel@lists.xen.org > https://lists.xen.org/xen-devel