From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Wed, 11 Sep 2002 10:19:53 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Wed, 11 Sep 2002 10:19:53 -0400 Received: from e35.co.us.ibm.com ([32.97.110.133]:3066 "EHLO e35.co.us.ibm.com") by vger.kernel.org with ESMTP id ; Wed, 11 Sep 2002 10:19:51 -0400 Date: Wed, 11 Sep 2002 19:59:39 +0530 From: Dipankar Sarma To: Robert Love Cc: Ingo Molnar , Linus Torvalds , Rusty Russell , Andrea Arcangeli , Paul McKenney , linux-kernel@vger.kernel.org Subject: Re: [PATCH] Read-Copy Update 2.5.34 Message-ID: <20020911195939.E28198@in.ibm.com> Reply-To: dipankar@in.ibm.com References: <20020911164940.C28198@in.ibm.com> <20020911175011.D28198@in.ibm.com> <1031753011.950.106.camel@phantasy> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5.1i In-Reply-To: <1031753011.950.106.camel@phantasy>; from rml@tech9.net on Wed, Sep 11, 2002 at 10:03:28AM -0400 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Sep 11, 2002 at 10:03:28AM -0400, Robert Love wrote: > On Wed, 2002-09-11 at 08:20, Dipankar Sarma wrote: > > > vanilla-2.5.34 rcu_poll-2.5.34 > > -------------- --------------- > > 80 , 40 , 1.593 1.569 > > 112 , 40 , 1.544 1.554 > > 144 , 40 , 1.595 1.552 > > 176 , 40 , 1.568 1.605 > > 198 , 40 , 1.562 1.577 > > 230 , 40 , 1.563 1.583 > > 244 , 40 , 1.671 1.638 > > > > Not sure how reliable these numbers are. > > And how bad is the performance drop from 2.5.34-preempt to > 2.5.34-preempt-rcu? > > I am glad you guys support kernel preemption (not that you have a chance > at this point) but I hope it was not an afterthought. Hi Robert, Sorry, I should have been more careful labelling them - those are 2.5.34-preempt vs 2.5.34-preempt-rcu numbers. I did them first because rcu-poll-preempt kernel has a conditinal branch in fast path and hence more interesting. I will publish the vanilla vs rcu_poll reflex numbers in a few minutes from now. The preemption support have been in RCU for a very long time. IIRC, I added it in around 2.5.14. See http://marc.theaimsgroup.com/?l=linux-kernel&m=102084967517192&w=2 Our OLS paper and presentation too deals with preemption - http://www.rdrop.com/users/paulmck/rclock/rcu.2002.07.08.pdf http://www.rdrop.com/users/paulmck/rclock/rclock.OLS.2002.07.08a.pdf Thanks -- Dipankar Sarma http://lse.sourceforge.net Linux Technology Center, IBM Software Lab, Bangalore, India.