From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3t4rL26lcKzDvPQ for ; Fri, 28 Oct 2016 15:26:18 +1100 (AEDT) Received: from pps.filterd (m0098393.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.17/8.16.0.17) with SMTP id u9S4Nsi8049886 for ; Fri, 28 Oct 2016 00:26:16 -0400 Received: from e23smtp04.au.ibm.com (e23smtp04.au.ibm.com [202.81.31.146]) by mx0a-001b2d01.pphosted.com with ESMTP id 26bvc220gg-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Fri, 28 Oct 2016 00:26:16 -0400 Received: from localhost by e23smtp04.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 28 Oct 2016 14:26:14 +1000 Received: from d23relay10.au.ibm.com (d23relay10.au.ibm.com [9.190.26.77]) by d23dlp01.au.ibm.com (Postfix) with ESMTP id 4BCC72CE8046 for ; Fri, 28 Oct 2016 15:26:12 +1100 (EST) Received: from d23av05.au.ibm.com (d23av05.au.ibm.com [9.190.234.119]) by d23relay10.au.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id u9S4QC5P5243232 for ; Fri, 28 Oct 2016 15:26:12 +1100 Received: from d23av05.au.ibm.com (localhost [127.0.0.1]) by d23av05.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id u9S4QAC2022653 for ; Fri, 28 Oct 2016 15:26:12 +1100 From: Pan Xinhui To: 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 Cc: benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au, mingo@redhat.com, peterz@infradead.org, paulmck@linux.vnet.ibm.com, will.deacon@arm.com, kernellwp@gmail.com, jgross@suse.com, pbonzini@redhat.com, bsingharora@gmail.com, boqun.feng@gmail.com, borntraeger@de.ibm.com, rkrcmar@redhat.com, David.Laight@ACULAB.COM, Pan Xinhui Subject: [PATCH v6 10/11] x86, xen: support vcpu preempted check Date: Fri, 28 Oct 2016 04:11:26 -0400 In-Reply-To: <1477642287-24104-1-git-send-email-xinhui.pan@linux.vnet.ibm.com> References: <1477642287-24104-1-git-send-email-xinhui.pan@linux.vnet.ibm.com> Message-Id: <1477642287-24104-11-git-send-email-xinhui.pan@linux.vnet.ibm.com> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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; } - /* * 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