From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeremy Fitzhardinge Subject: Re: [PATCH RFC V9 0/19] Paravirtualized ticket spinlocks Date: Sat, 01 Jun 2013 13:28:00 -0700 Message-ID: <51AA5950.6050603@goop.org> References: <20130601082145.22955.33596.sendpatchset@codeblue> <20130601201442.GP6123@two.firstfloor.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: x86@kernel.org, kvm@vger.kernel.org, linux-doc@vger.kernel.org, peterz@infradead.org, drjones@redhat.com, virtualization@lists.linux-foundation.org, srivatsa.vaddagiri@gmail.com, hpa@zytor.com, stefano.stabellini@eu.citrix.com, xen-devel@lists.xensource.com, gleb@redhat.com, Raghavendra K T , agraf@suse.de, mingo@redhat.com, habanero@linux.vnet.ibm.com, konrad.wilk@oracle.com, ouyang@cs.pitt.edu, mtosatti@redhat.com, avi.kivity@gmail.com, tglx@linutronix.de, chegu_vinod@hp.com, gregkh@suse.de, linux-kernel@vger.kernel.org, attilio.rao@citrix.com, pbonzini@redhat.com, torvalds@linux-foundation.org, stephan.diestelhorst@amd.com To: Andi Kleen Return-path: In-Reply-To: <20130601201442.GP6123@two.firstfloor.org> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org List-Id: kvm.vger.kernel.org On 06/01/2013 01:14 PM, Andi Kleen wrote: > FWIW I use the paravirt spinlock ops for adding lock elision > to the spinlocks. Does lock elision still use the ticketlock algorithm/structure, or are they different? If they're still basically ticketlocks, then it seems to me that they're complimentary - hle handles the fastpath, and pv the slowpath. > This needs to be done at the top level (so the level you're removing) > > However I don't like the pv mechanism very much and would > be fine with using an static key hook in the main path > like I do for all the other lock types. Right. J From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755234Ab3FAUhQ (ORCPT ); Sat, 1 Jun 2013 16:37:16 -0400 Received: from claw.goop.org ([74.207.240.146]:51286 "EHLO claw.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751915Ab3FAUhP (ORCPT ); Sat, 1 Jun 2013 16:37:15 -0400 X-Greylist: delayed 551 seconds by postgrey-1.27 at vger.kernel.org; Sat, 01 Jun 2013 16:37:14 EDT Message-ID: <51AA5950.6050603@goop.org> Date: Sat, 01 Jun 2013 13:28:00 -0700 From: Jeremy Fitzhardinge User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130514 Thunderbird/17.0.6 MIME-Version: 1.0 To: Andi Kleen CC: Raghavendra K T , gleb@redhat.com, mingo@redhat.com, x86@kernel.org, konrad.wilk@oracle.com, hpa@zytor.com, pbonzini@redhat.com, linux-doc@vger.kernel.org, habanero@linux.vnet.ibm.com, xen-devel@lists.xensource.com, peterz@infradead.org, mtosatti@redhat.com, stefano.stabellini@eu.citrix.com, attilio.rao@citrix.com, ouyang@cs.pitt.edu, gregkh@suse.de, agraf@suse.de, chegu_vinod@hp.com, torvalds@linux-foundation.org, avi.kivity@gmail.com, tglx@linutronix.de, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, stephan.diestelhorst@amd.com, riel@redhat.com, drjones@redhat.com, virtualization@lists.linux-foundation.org, srivatsa.vaddagiri@gmail.com Subject: Re: [PATCH RFC V9 0/19] Paravirtualized ticket spinlocks References: <20130601082145.22955.33596.sendpatchset@codeblue> <20130601201442.GP6123@two.firstfloor.org> In-Reply-To: <20130601201442.GP6123@two.firstfloor.org> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 06/01/2013 01:14 PM, Andi Kleen wrote: > FWIW I use the paravirt spinlock ops for adding lock elision > to the spinlocks. Does lock elision still use the ticketlock algorithm/structure, or are they different? If they're still basically ticketlocks, then it seems to me that they're complimentary - hle handles the fastpath, and pv the slowpath. > This needs to be done at the top level (so the level you're removing) > > However I don't like the pv mechanism very much and would > be fine with using an static key hook in the main path > like I do for all the other lock types. Right. J