From mboxrd@z Thu Jan 1 00:00:00 1970 From: Unai Uribarri Subject: Re: [PATCH 1/1] af_packet: don't enable timestamps in mmap'ed sockets Date: Fri, 10 Aug 2007 13:55:07 +0200 Message-ID: <1186746907.24669.107.camel@localhost.localdomain> References: <1186669314.24669.56.camel@localhost.localdomain> <20070809143322.GA5345@2ka.mipt.ru> <1186683234.24669.65.camel@localhost.localdomain> <20070809181823.GA32449@2ka.mipt.ru> <1186685061.24669.76.camel@localhost.localdomain> <20070810083418.GA25479@2ka.mipt.ru> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org To: Evgeniy Polyakov Return-path: Received: from mta-mad.optenet.com ([213.27.232.70]:54409 "EHLO mta-mad.optenet.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S936829AbXHJLzN (ORCPT ); Fri, 10 Aug 2007 07:55:13 -0400 In-Reply-To: <20070810083418.GA25479@2ka.mipt.ru> Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On vie, 2007-08-10 at 12:34 +0400, Evgeniy Polyakov wrote: > Hi Unai. > > On Thu, Aug 09, 2007 at 08:44:21PM +0200, Unai Uribarri (unai.uribarri@optenet.com) wrote: > > There is another option: > > > > 1. Move timestampt activation to packet_set_ring(), so it's activated > > only once at setup instead of every time a packet arrives. > > Does this break existing systems which expects timestamp be turned on > always if there are packet sockets. > Well, current behaviour is that all packets get always timestamped if the socket has a reception ring. We are just activating it a bit sooner at the setsockopt(SOL_PACKET, PACKET_RX_RING) call instead of waiting until the reception of the first packet. And current applications can't disable it if we use a new socket option. So I can see how an application can break. > > 2. Fix sock_setsockopt() so setting SO_TIMESTAMP to 0 effectively > > disables timestamp. > > This breaks compatibility. Add new socket option, which will really > disable it and do all your logic, but not breaking existing > applications. > Is SO_TIMESTAMP2 a valid name? I can't imagine how to call it.