Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753126AbaDCRYe (ORCPT ); Thu, 3 Apr 2014 13:24:34 -0400 Received: from aserp1040.oracle.com ([141.146.126.69]:22018 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752875AbaDCRYb (ORCPT ); Thu, 3 Apr 2014 13:24:31 -0400 Date: Thu, 3 Apr 2014 13:23:34 -0400 From: Konrad Rzeszutek Wilk To: Waiman Long Cc: Marcos Matsunaga , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Peter Zijlstra , linux-arch@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, xen-devel@lists.xenproject.org, kvm@vger.kernel.org, Paolo Bonzini , "Paul E. McKenney" , Rik van Riel , Linus Torvalds , Raghavendra K T , David Vrabel , Oleg Nesterov , Gleb Natapov , Aswin Chandramouleeswaran , Scott J Norton , Chegu Vinod , boris.ostrovsky@oracle.com Subject: Re: [PATCH v8 00/10] qspinlock: a 4-byte queue spinlock with PV support Message-ID: <20140403172333.GA3877@localhost.localdomain> References: <1396445259-27670-1-git-send-email-Waiman.Long@hp.com> <20140402143201.GF12188@phenom.dumpdata.com> <533C7485.3030203@hp.com> <533CC309.3020607@hp.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <533CC309.3020607@hp.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-Source-IP: acsinet21.oracle.com [141.146.126.237] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Apr 02, 2014 at 10:10:17PM -0400, Waiman Long wrote: > On 04/02/2014 04:35 PM, Waiman Long wrote: > >On 04/02/2014 10:32 AM, Konrad Rzeszutek Wilk wrote: > >>On Wed, Apr 02, 2014 at 09:27:29AM -0400, Waiman Long wrote: > >>>N.B. Sorry for the duplicate. This patch series were resent as the > >>> original one was rejected by the vger.kernel.org list server > >>> due to long header. There is no change in content. > >>> > >>>v7->v8: > >>> - Remove one unneeded atomic operation from the slowpath, thus > >>> improving performance. > >>> - Simplify some of the codes and add more comments. > >>> - Test for X86_FEATURE_HYPERVISOR CPU feature bit to enable/disable > >>> unfair lock. > >>> - Reduce unfair lock slowpath lock stealing frequency depending > >>> on its distance from the queue head. > >>> - Add performance data for IvyBridge-EX CPU. > >>FYI, your v7 patch with 32 VCPUs (on a 32 cpu socket machine) on an > >>HVM guest under Xen after a while stops working. The workload > >>is doing 'make -j32' on the Linux kernel. > >> > >>Completely unresponsive. Thoughts? > >> > > > >Thank for reporting that. I haven't done that much testing on Xen. > >My focus was in KVM. I will perform more test on Xen to see if I > >can reproduce the problem. > > > > BTW, does the halting and sending IPI mechanism work in HVM? I saw Yes. > that in RHEL7, PV spinlock was explicitly disabled when in HVM mode. > However, this piece of code isn't in upstream code. So I wonder if > there is problem with that. The PV ticketlock fixed it for HVM. It was disabled before because the PV guests were using bytelocks while the HVM were using ticketlocks and you couldnt' swap in PV bytelocks for ticketlocks during startup. > > -Longman -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/