From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: pktgen question Date: Mon, 24 Sep 2007 10:40:16 -0700 (PDT) Message-ID: <20070924.104016.74732763.davem@davemloft.net> References: <1190571527.4256.78.camel@localhost> <46F75968.4010307@candelatech.com> <46F7C185.1030202@opengridcomputing.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: greearb@candelatech.com, hadi@cyberus.ca, johnpol@2ka.mipt.ru, netdev@vger.kernel.org, Robert.Olsson@data.slu.se To: swise@opengridcomputing.com Return-path: Received: from 74-93-104-97-Washington.hfc.comcastbusiness.net ([74.93.104.97]:48099 "EHLO sunset.davemloft.net" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1751117AbXIXRkQ (ORCPT ); Mon, 24 Sep 2007 13:40:16 -0400 In-Reply-To: <46F7C185.1030202@opengridcomputing.com> Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org From: Steve Wise Date: Mon, 24 Sep 2007 08:54:13 -0500 > I think pktgen should be cloning the skbs using skb_clone(). Then it > will work for all devices, eh? The problem is that skb_clone() is (relatively) expensive and pktgen is trying to just grab a reference to the SKB in the absolutely cheapest way possible. In my personal opinion, I think what the drivers that don't work with pktgen are doing is wrong and they should find another way to pass state around other than to depend upon being able to use the ->cb[] area at-will.