From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752711AbbIWR6B (ORCPT ); Wed, 23 Sep 2015 13:58:01 -0400 Received: from mail-wi0-f182.google.com ([209.85.212.182]:35089 "EHLO mail-wi0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750903AbbIWR57 (ORCPT ); Wed, 23 Sep 2015 13:57:59 -0400 Subject: Re: [PATCH tip/core/rcu 3/4] md/bitmap: Fix list_entry_rcu usage To: paulmck@linux.vnet.ibm.com References: <1431470787-4702-3-git-send-email-paulmck@linux.vnet.ibm.com> <20150512223853.55e0ed90@grimm.local.home> <20150513125839.371ef677@notabene.brown> <5557819E.1060001@gmail.com> <20150518120647.0c3cecd8@notabene.brown> <20150518094321.2012a66a@gandalf.local.home> <20150519220725.GA6776@linux.vnet.ibm.com> <20150911230554.GA26655@linux.vnet.ibm.com> <55F54AA9.3020102@gmail.com> <20150913161023.GM4029@linux.vnet.ibm.com> <20150922205000.GA29408@linux.vnet.ibm.com> Cc: Steven Rostedt , NeilBrown , linux-kernel@vger.kernel.org, mingo@kernel.org, laijs@cn.fujitsu.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@efficios.com, josh@joshtriplett.org, tglx@linutronix.de, peterz@infradead.org, dhowells@redhat.com, edumazet@google.com, dvhart@linux.intel.com, fweisbec@gmail.com, oleg@redhat.com, bobby.prani@gmail.com, wangyun@linux.vnet.ibm.com From: Patrick Marlier Message-ID: <5602E821.800@gmail.com> Date: Wed, 23 Sep 2015 19:57:53 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.2.0 MIME-Version: 1.0 In-Reply-To: <20150922205000.GA29408@linux.vnet.ibm.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09/22/2015 10:50 PM, Paul E. McKenney wrote: > On Sun, Sep 13, 2015 at 09:10:24AM -0700, Paul E. McKenney wrote: >> On Sun, Sep 13, 2015 at 12:06:33PM +0200, Patrick Marlier wrote: > > [ . . . ] > >>> Paul, >>> >>> This sounds good to me. It should fix the performance issue (will >>> check with my benchmark). >> >> Thank you, looking forward to seeing the results! > > Just following up -- how is the benchmarking going? Note that in my module I am using the kernel version 3.16.0-31 (I ported your change). Here the results of my benchmark that tests rculist in the case of read only. # 1st column : The number of threads # 2nd : ops/s the original version # 3rd : ops/s your version with lockless_dereference 1 883923 1747554 2 1741441 3543062 3 2462360 5103647 4 3437273 7176608 6 5155803 9812348 8 6718111 13330050 10 8519227 17458294 12 9773632 20298897 14 11555198 23191424 16 11643264 25125712 I get same performance with my patch. So indeed it fixes the performance problem I was seeing. Thanks a lot! -- Pat