From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753180AbcGFHr2 (ORCPT ); Wed, 6 Jul 2016 03:47:28 -0400 Received: from mx2.suse.de ([195.135.220.15]:55831 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752718AbcGFHrY (ORCPT ); Wed, 6 Jul 2016 03:47:24 -0400 Subject: Re: [PATCH v2 0/4] implement vcpu preempted check To: Pan Xinhui References: <1467124991-13164-1-git-send-email-xinhui.pan@linux.vnet.ibm.com> <20160706065255.GH30909@twins.programming.kicks-ass.net> Cc: Peter Zijlstra , linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, virtualization@lists.linux-foundation.org, linux-s390@vger.kernel.org, mingo@redhat.com, mpe@ellerman.id.au, paulus@samba.org, benh@kernel.crashing.org, paulmck@linux.vnet.ibm.com, waiman.long@hpe.com, will.deacon@arm.com, boqun.feng@gmail.com, dave@stgolabs.net, schwidefsky@de.ibm.com, pbonzini@redhat.com, xen-devel-request@lists.xenproject.org From: Juergen Gross Message-ID: <577CB786.8000902@suse.com> Date: Wed, 6 Jul 2016 09:47:18 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.7.0 MIME-Version: 1.0 In-Reply-To: <20160706065255.GH30909@twins.programming.kicks-ass.net> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 06/07/16 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? Xen support of this interface should be rather easy. Could you please Cc: xen-devel-request@lists.xenproject.org in the next version? Juergen