From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paul Chavent Subject: Re: [PATCH] net-packet: tx timestamping on tpacket ring Date: Mon, 15 Apr 2013 09:37:30 +0200 Message-ID: <516BAE3A.5020508@onera.fr> References: <1365879412-9541-1-git-send-email-willemb@google.com> <5169D9C8.8010504@redhat.com> <516A8A60.5020003@redhat.com> <20130414130726.GB2871@netboy> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Daniel Borkmann , Willem de Bruijn , Eric Dumazet , daniel.borkmann@tik.ee.ethz.ch, xemul@parallels.com, ebiederm@xmission.com, netdev@vger.kernel.org To: Richard Cochran Return-path: Received: from briaree.onecert.fr ([134.212.190.4]:32969 "EHLO briaree.onecert.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751541Ab3DOHly (ORCPT ); Mon, 15 Apr 2013 03:41:54 -0400 In-Reply-To: <20130414130726.GB2871@netboy> Sender: netdev-owner@vger.kernel.org List-ID: On 04/14/2013 03:07 PM, Richard Cochran wrote: > On Sun, Apr 14, 2013 at 12:52:16PM +0200, Daniel Borkmann wrote: >> >> While going a bit more through the code, I'm wondering .. if we want to support >> TX timestamps, could we also support SW _and_ HW timestamps e.g. similar as in >> sock_recv_timestamp()? I'm asking, because we already allow setting the flags >> for it via sock_tx_timestamp(). This might be good, if possible. > > And while you are at it, you could also fix the receive code. > > As it stand now, it is fairly useless, since there is no way for user > space to tell which kind of time stamp has been reported. In fact, the > code will silently intermingle hardware and software time stamps. That > is surely a mean trick to play on the users. Isn't it the one that the user ask with setsockopt(fd, SOL_PACKET, PACKET_TIMESTAMP, ×tamping, sizeof(timestamping)) ? However, i wonder why you added an other sockopt that do the same thing as SOL_SOCKET/SO_TIMESTAMPING sockopt ? Paul.