From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Zijlstra Subject: Re: [RFC PATCH v2] Implement Batched (group) ticket lock Date: Tue, 1 Jul 2014 10:05:37 +0200 Message-ID: <20140701080537.GH6758@twins.programming.kicks-ass.net> References: <1403947024-3193-1-git-send-email-raghavendra.kt@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit 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 To: Raghavendra K T Return-path: Content-Disposition: inline In-Reply-To: <1403947024-3193-1-git-send-email-raghavendra.kt@linux.vnet.ibm.com> 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 List-Id: kvm.vger.kernel.org On Sat, Jun 28, 2014 at 02:47:04PM +0530, Raghavendra K T wrote: > In virtualized environment there are mainly three problems > related to spinlocks that affects performance. > 1. LHP (lock holder preemption) > 2. Lock Waiter Preemption (LWP) > 3. Starvation/fairness > > Though Ticketlocks solve fairness problem it worsens LWP, LHP problems. Though > pv-ticketlocks tried to address these problems we can further improve at the > cost of relaxed fairness. The following patch tries to achieve that by grouping > (batched) ticketlocks. And here I stop reading and ignore this patch, right? Why should I look at this?