From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752740AbbCJM6E (ORCPT ); Tue, 10 Mar 2015 08:58:04 -0400 Received: from mail-lb0-f176.google.com ([209.85.217.176]:40599 "EHLO mail-lb0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752311AbbCJM57 (ORCPT ); Tue, 10 Mar 2015 08:57:59 -0400 From: Rasmus Villemoes To: Tejun Heo Cc: Joe Perches , linux-kernel@vger.kernel.org, "Peter Zijlstra \(Intel\)" , Andrew Morton Subject: Re: [RFC] lib/vsprintf.c: Even faster decimal conversion Organization: D03 References: <1424476281-26873-1-git-send-email-linux@rasmusvillemoes.dk> <87r3t3eafm.fsf@rasmusvillemoes.dk> <1425571413.31859.1.camel@perches.com> <20150305161051.GE23912@htj.duckdns.org> <87egp384m0.fsf@rasmusvillemoes.dk> <87zj7l6sdo.fsf@rasmusvillemoes.dk> <20150310124220.GA28730@htj.duckdns.org> X-Hashcash: 1:20:150310:akpm@linux-foundation.org::UU7ok7sMkRoBpDFd:0000000000000000000000000000000000001A7q X-Hashcash: 1:20:150310:peterz@infradead.org::ltjQJ2v5xajlhYfu:000000000000000000000000000000000000000004O6g X-Hashcash: 1:20:150310:tj@kernel.org::PYoYshAeMbR5JuYv:00005Igk X-Hashcash: 1:20:150310:linux-kernel@vger.kernel.org::6vRUFwMittqk6mop:0000000000000000000000000000000008HjS X-Hashcash: 1:20:150310:joe@perches.com::6M12fkGvN5cvQRko:00I46i Date: Tue, 10 Mar 2015 13:57:56 +0100 In-Reply-To: <20150310124220.GA28730@htj.duckdns.org> (Tejun Heo's message of "Tue, 10 Mar 2015 08:42:20 -0400") Message-ID: <87vbi96mcr.fsf@rasmusvillemoes.dk> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Mar 10 2015, Tejun Heo wrote: > Hello, > > On Tue, Mar 10, 2015 at 11:47:47AM +0100, Rasmus Villemoes wrote: >> I can't explain why num_to_str apparently becomes slightly slower (the >> patch essentially didn't touch it), but the put_dec_ helpers in any case >> make up for that. > > Unrelated code changes affecting performance in seemingly random way > isn't too uncommon. A lot of it arises from cacheline behaviors. The > effect is sometimes surprisingly big. > > Generally looks pretty good to me. Thanks. > Andrew, can you please pick this patch up? No, please give me a day or two to post a new version (I purposely wrote not-yet-signed-off-by because I want to clean up both the patch and the commit message - I just wanted to get the code out there early in the release cycle). Rasmus