Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751014AbVLGMlj (ORCPT ); Wed, 7 Dec 2005 07:41:39 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751013AbVLGMlj (ORCPT ); Wed, 7 Dec 2005 07:41:39 -0500 Received: from perninha.conectiva.com.br ([200.140.247.100]:42221 "EHLO perninha.conectiva.com.br") by vger.kernel.org with ESMTP id S1751008AbVLGMlh (ORCPT ); Wed, 7 Dec 2005 07:41:37 -0500 Date: Wed, 7 Dec 2005 10:41:24 -0200 From: Luiz Fernando Capitulino To: Arjan van de Ven Cc: oliver@neukum.org, linux-usb-devel@lists.sourceforge.net, ehabkost@mandriva.com, gregkh@suse.de, linux-kernel@vger.kernel.org Subject: Re: [linux-usb-devel] Re: [PATCH 00/10] usb-serial: Switches from spin lock to atomic_t. Message-Id: <20051207104124.652237fb.lcapitulino@mandriva.com.br> In-Reply-To: <1133958878.2869.21.camel@laptopd505.fenrus.org> 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> <1133958878.2869.21.camel@laptopd505.fenrus.org> Organization: Mandriva X-Mailer: Sylpheed version 1.0.5 (GTK+ 1.2.10; i586-mandriva-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 979 Lines: 33 On Wed, 07 Dec 2005 13:34:38 +0100 Arjan van de Ven wrote: | 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? In the 'usb_serial_port', my patch number nine removes the spin lock. | spin_unlock in principle runs unlocked on x86 at least | (except for ppro workarounds but those are/should be optional) | | -- Luiz Fernando N. Capitulino - 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/