From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757329Ab2EIHfz (ORCPT ); Wed, 9 May 2012 03:35:55 -0400 Received: from mail-ob0-f174.google.com ([209.85.214.174]:61234 "EHLO mail-ob0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753198Ab2EIHfx convert rfc822-to-8bit (ORCPT ); Wed, 9 May 2012 03:35:53 -0400 MIME-Version: 1.0 In-Reply-To: <87sjfcfynb.fsf@rustcorp.com.au> References: <87ehtf3lqh.fsf@rustcorp.com.au> <20120227155338.7b5110cd.akpm@linux-foundation.org> <20120228112422.GC11324@alboin.amr.corp.intel.com> <87ipijzfwn.fsf@rustcorp.com.au> <20120420112149.GH25458@amd.local0.net> <87sjfcfynb.fsf@rustcorp.com.au> Date: Wed, 9 May 2012 17:35:53 +1000 Message-ID: Subject: Re: [PATCH 3/3] brlocks/lglocks: turn into functions From: Nick Piggin To: Rusty Russell Cc: Nick Piggin , Andi Kleen , Andrew Morton , linux-kernel , Alexander Viro , "Srivatsa S. Bhat" , linux-fsdevel@vger.kernel.org Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 7 May 2012 13:39, Rusty Russell wrote: > On Fri, 20 Apr 2012 21:21:49 +1000, Nick Piggin wrote: >> This still not merged? > > No, I've been away.  I've put it in -next for tomorrow, though I'm not > sure what the best way to get it to Linus next merge window. > >> There is a reason, which is performance. Extra function call, but also >> IIRC the percpu accessor was not so fast doing it this way. Maybe >> that's improved... >> >> So what's the performance difference? > > What benchmarks you usually run?  Feel free to try it out and report > back; I only have small hardware here. Nothing big. The actual scalability should be unchanged, because you're not going to be dirtying any shared cachelines. It's the use of dynamic percpu allocator and out of line calls etc which will slow down straight line performance. How many microseconds does it take to stat("./dir1/dir2/myfile"), for example? `git diff` of a large tree, for something more realistic but still going to exercise that path. From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nick Piggin Subject: Re: [PATCH 3/3] brlocks/lglocks: turn into functions Date: Wed, 9 May 2012 17:35:53 +1000 Message-ID: References: <87ehtf3lqh.fsf@rustcorp.com.au> <20120227155338.7b5110cd.akpm@linux-foundation.org> <20120228112422.GC11324@alboin.amr.corp.intel.com> <87ipijzfwn.fsf@rustcorp.com.au> <20120420112149.GH25458@amd.local0.net> <87sjfcfynb.fsf@rustcorp.com.au> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Nick Piggin , Andi Kleen , Andrew Morton , linux-kernel , Alexander Viro , "Srivatsa S. Bhat" , linux-fsdevel@vger.kernel.org To: Rusty Russell Return-path: Received: from mail-ob0-f174.google.com ([209.85.214.174]:61234 "EHLO mail-ob0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753198Ab2EIHfx convert rfc822-to-8bit (ORCPT ); Wed, 9 May 2012 03:35:53 -0400 In-Reply-To: <87sjfcfynb.fsf@rustcorp.com.au> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On 7 May 2012 13:39, Rusty Russell wrote: > On Fri, 20 Apr 2012 21:21:49 +1000, Nick Piggin w= rote: >> This still not merged? > > No, I've been away. =C2=A0I've put it in -next for tomorrow, though I= 'm not > sure what the best way to get it to Linus next merge window. > >> There is a reason, which is performance. Extra function call, but al= so >> IIRC the percpu accessor was not so fast doing it this way. Maybe >> that's improved... >> >> So what's the performance difference? > > What benchmarks you usually run? =C2=A0Feel free to try it out and re= port > back; I only have small hardware here. Nothing big. The actual scalability should be unchanged, because you're not going to be dirtying any shared cachelines. It's the use of dynamic percpu allocator and out of line calls etc which will slow down straigh= t line performance. How many microseconds does it take to stat("./dir1/dir2/myfile"), for example? `git diff` of a large tree, for something more realistic but still goin= g to exercise that path. -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel= " in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html