Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750953AbVLGMer (ORCPT ); Wed, 7 Dec 2005 07:34:47 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750971AbVLGMer (ORCPT ); Wed, 7 Dec 2005 07:34:47 -0500 Received: from pentafluge.infradead.org ([213.146.154.40]:41134 "EHLO pentafluge.infradead.org") by vger.kernel.org with ESMTP id S1750964AbVLGMeq (ORCPT ); Wed, 7 Dec 2005 07:34:46 -0500 Subject: Re: [linux-usb-devel] Re: [PATCH 00/10] usb-serial: Switches from spin lock to atomic_t. From: Arjan van de Ven To: Luiz Fernando Capitulino Cc: oliver@neukum.org, linux-usb-devel@lists.sourceforge.net, ehabkost@mandriva.com, gregkh@suse.de, linux-kernel@vger.kernel.org In-Reply-To: <20051207103025.7f4979a0.lcapitulino@mandriva.com.br> References: <20051206095610.29def5e7.lcapitulino@mandriva.com.br> <20051206194041.GA22890@suse.de> <20051206201340.GB20451@duckman.conectiva> <200512062348.14349.oliver@neukum.org> <20051207102419.1f395664.lcapitulino@mandriva.com.br> <1133958433.2869.19.camel@laptopd505.fenrus.org> <20051207103025.7f4979a0.lcapitulino@mandriva.com.br> Content-Type: text/plain Date: Wed, 07 Dec 2005 13:34:38 +0100 Message-Id: <1133958878.2869.21.camel@laptopd505.fenrus.org> Mime-Version: 1.0 X-Mailer: Evolution 2.2.3 (2.2.3-2.fc4) Content-Transfer-Encoding: 7bit X-Spam-Score: 1.8 (+) X-Spam-Report: SpamAssassin version 3.0.4 on pentafluge.infradead.org summary: Content analysis details: (1.8 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- 0.1 RCVD_IN_SORBS_DUL RBL: SORBS: sent directly from dynamic IP address [213.93.14.173 listed in dnsbl.sorbs.net] 1.7 RCVD_IN_NJABL_DUL RBL: NJABL: dialup sender did non-local SMTP [213.93.14.173 listed in combined.njabl.org] X-SRS-Rewrite: SMTP reverse-path rewritten from by pentafluge.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 753 Lines: 22 On Wed, 2005-12-07 at 10:30 -0200, Luiz Fernando Capitulino wrote: > On Wed, 07 Dec 2005 13:27:13 +0100 > Arjan van de Ven wrote: > > | > | > Isn't it right? Is the URB write so fast that switching to atomic_t > | > doesn't pay-off? > | > | an atomic_t access and a spinlock are basically the same price... so > | what's the payoff ? > > One lock less, where? spin_unlock in principle runs unlocked on x86 at least (except for ppro workarounds but those are/should be optional) - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/