From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jesper Dangaard Brouer Subject: Re: [net-next PATCH] pktgen: add flag NO_TIMESTAMP to disable timestamping Date: Fri, 29 Aug 2014 21:02:54 +0200 Message-ID: <20140829210254.360f74bf@redhat.com> References: <20140828161447.6652.59388.stgit@dragon> <1409329026.3173.93.camel@edumazet-glaptop2.roam.corp.google.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: "David S. Miller" , netdev@vger.kernel.org, Ben Greear , Robert Olsson , brouer@redhat.com To: Eric Dumazet Return-path: Received: from mx1.redhat.com ([209.132.183.28]:36404 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753382AbaH2TDK (ORCPT ); Fri, 29 Aug 2014 15:03:10 -0400 In-Reply-To: <1409329026.3173.93.camel@edumazet-glaptop2.roam.corp.google.com> Sender: netdev-owner@vger.kernel.org List-ID: On Fri, 29 Aug 2014 09:17:06 -0700 Eric Dumazet wrote: > On Thu, 2014-08-28 at 18:14 +0200, Jesper Dangaard Brouer wrote: > > Then testing the TX limits of the stack, then it is useful to > > be-able to disable the do_gettimeofday() timetamping on every packet. > > > > This implements a pktgen flag NO_TIMESTAMP which will disable this > > call to do_gettimeofday(). > > > > The performance change on (my system E5-2695) with skb_clone=0, goes > > from TX 2,423,751 pps to 2,567,165 pps with flag NO_TIMESTAMP. Thus, > > the cost of do_gettimeofday() or saving is approx 23 nanosec. > > I guess using local_clock() would provide an accurate and less expensive > timestamp, if a timestamp is needed. Sure, but I don't need this timestamp, thus I added an option to disable it. -- Best regards, Jesper Dangaard Brouer MSc.CS, Sr. Network Kernel Developer at Red Hat Author of http://www.iptv-analyzer.org LinkedIn: http://www.linkedin.com/in/brouer