From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753286Ab3J2IbK (ORCPT ); Tue, 29 Oct 2013 04:31:10 -0400 Received: from smtprelay0022.hostedemail.com ([216.40.44.22]:46682 "EHLO smtprelay.hostedemail.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751510Ab3J2IbH (ORCPT ); Tue, 29 Oct 2013 04:31:07 -0400 X-Session-Marker: 6A6F6540706572636865732E636F6D X-Spam-Summary: 2,0,0,,d41d8cd98f00b204,joe@perches.com,:::::::::::::,RULES_HIT:41:355:379:541:599:973:988:989:1260:1261:1277:1311:1313:1314:1345:1359:1373:1437:1515:1516:1518:1534:1539:1593:1594:1711:1714:1730:1747:1777:1792:2194:2199:2393:2559:2562:2828:2895:3138:3139:3140:3141:3142:3351:3622:3865:3866:3867:3871:3873:4321:5007:7652:7903:10004:10400:10848:11026:11232:11473:11657:11658:11914:12043:12296:12517:12519:12740:13019:13069:13095:13311:13357:13972,0,RBL:none,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:fn,MSBL:0,DNSBL:none,Custom_rules:0:0:0 X-HE-Tag: body12_435b2cf2db938 X-Filterd-Recvd-Size: 1532 Message-ID: <1383035461.2713.1.camel@joe-AO722> Subject: Re: [PATCH v2] can: c_can: Speed up rx_poll function From: Joe Perches To: Markus Pargmann Cc: Marc Kleine-Budde , Wolfgang Grandegger , linux-can@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, kernel@pengutronix.de Date: Tue, 29 Oct 2013 01:31:01 -0700 In-Reply-To: <1383035267-19604-1-git-send-email-mpa@pengutronix.de> References: <1383035267-19604-1-git-send-email-mpa@pengutronix.de> Content-Type: text/plain; charset="ISO-8859-1" X-Mailer: Evolution 3.8.4-0ubuntu1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2013-10-29 at 09:27 +0100, Markus Pargmann wrote: > This patch speeds up the rx_poll function by reducing the number of > register reads. [] > The third change is to replace the for-loop by a find_next_bit loop. You need to update the commit message. > diff --git a/drivers/net/can/c_can/c_can.c b/drivers/net/can/c_can/c_can.c [] > @@ -798,17 +798,19 @@ static int c_can_do_rx_poll(struct net_device *dev, int quota) [] > + while (quota > 0 && (val = priv->read_reg(priv, C_CAN_INTPND1_REG))) { > + while ((msg_obj = ffs(val)) && quota > 0) { > + val &= ~BIT(msg_obj - 1);