From mboxrd@z Thu Jan 1 00:00:00 1970 From: Raghavendra K T Subject: Re: [RFC PATCH v2] Implement Batched (group) ticket lock Date: Tue, 01 Jul 2014 16:41:06 +0530 Message-ID: <53B2974A.6010809@linux.vnet.ibm.com> References: <1403947024-3193-1-git-send-email-raghavendra.kt@linux.vnet.ibm.com> <20140701080537.GH6758@twins.programming.kicks-ass.net> <53B282E9.6060806@linux.vnet.ibm.com> <20140701095521.GO6758@twins.programming.kicks-ass.net> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20140701095521.GO6758@twins.programming.kicks-ass.net> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: Peter Zijlstra Cc: jeremy@goop.org, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, paul.gortmaker@windriver.com, hpa@zytor.com, ak@linux.intel.com, gleb@redhat.com, x86@kernel.org, mingo@redhat.com, xen-devel@lists.xenproject.org, paulmck@linux.vnet.ibm.com, riel@redhat.com, konrad.wilk@oracle.com, oleg@redhat.com, davej@redhat.com, tglx@linutronix.de, fernando_b1@lab.ntt.co.jp, chegu_vinod@hp.com, waiman.long@hp.com, linux-kernel@vger.kernel.org, pbonzini@redhat.com, torvalds@linux-foundation.org List-Id: virtualization@lists.linuxfoundation.org >> >> For baremetal we continue to have 'fully fair ticketlock' with this patch >> series. >> > > But but but, we're looking at removing ticket locks. So why do we want > to invest in them now? > I have nothing against qspinlock. I am happy to test it/add any bit to it if I could. With this patch we get excellent performance for guest with the unmodified kernel without affecting host. My test on guest with batch_size =16,32 showed even better performance bs=16 bs=32 ebizzy_0.5x 0.14 0.90 ebizzy_1.0x 3.57 7.52 ebizzy_1.5x 58.97 67.65 ebizzy_2.0x 121.55 136.45