From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753564AbbKZVDj (ORCPT ); Thu, 26 Nov 2015 16:03:39 -0500 Received: from mail-wm0-f42.google.com ([74.125.82.42]:38830 "EHLO mail-wm0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753510AbbKZVDi (ORCPT ); Thu, 26 Nov 2015 16:03:38 -0500 From: Rasmus Villemoes To: Joe Perches Cc: Jiri Kosina , linux-input@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] HID: debug: improve hid_debug_event() Organization: D03 References: <1448368427-1669-1-git-send-email-linux@rasmusvillemoes.dk> <1448483516.20113.61.camel@perches.com> X-Hashcash: 1:20:151126:jikos@kernel.org::Za0ZblUCaOdIRWd/:00Td6 X-Hashcash: 1:20:151126:joe@perches.com::+pKJO9AfbGJezBLC:000DXg X-Hashcash: 1:20:151126:linux-kernel@vger.kernel.org::oaKtDkM7wH3yDHjF:000000000000000000000000000000000AAEa X-Hashcash: 1:20:151126:linux-input@vger.kernel.org::vRY6ENp5+igBvcrV:00000000000000000000000000000000009Nhb Date: Thu, 26 Nov 2015 22:03:35 +0100 In-Reply-To: <1448483516.20113.61.camel@perches.com> (Joe Perches's message of "Wed, 25 Nov 2015 12:31:56 -0800") Message-ID: <87a8q0eamw.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 Wed, Nov 25 2015, Joe Perches wrote: >> spin_lock_irqsave(&hdev->debug_list_lock, flags); >> list_for_each_entry(list, &hdev->debug_list, node) { >> - for (i = 0; i < strlen(buf); i++) >> + for (i = 0; buf[i]; i++) >> list->hid_debug_buf[(list->tail + i) % HID_DEBUG_BUFSIZE] = >> buf[i]; >> list->tail = (list->tail + i) % HID_DEBUG_BUFSIZE; > > trivia: > > The code might look nicer if (list->tail + i) % HID_DEBUG_BUFSIZE > was stored into a temporary. Maybe. > Maybe use an if >= BUFSIZE to avoid a % Nah, that would likely be worse; both a cmov and a conditional jump are probably more expensive than a simple '& 0x1ff' which the % should compile to (provided the expression is unsigned). Rasmus