From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Vrabel Subject: Re: [PATCHv2 net-next] xen-netback: remove unconditional __pskb_pull_tail() in guest Tx path Date: Wed, 5 Nov 2014 11:01:35 +0000 Message-ID: <545A038F.2020303@citrix.com> References: <1415184622-19421-1-git-send-email-david.vrabel@citrix.com> <1415185138.11486.87.camel@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail6.bemta5.messagelabs.com ([195.245.231.135]) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1XlyLL-0003yu-Tg for xen-devel@lists.xenproject.org; Wed, 05 Nov 2014 11:01:40 +0000 In-Reply-To: <1415185138.11486.87.camel@citrix.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Ian Campbell Cc: xen-devel@lists.xenproject.org, Malcolm Crossley , Paul Durrant , Wei Liu List-Id: xen-devel@lists.xenproject.org On 05/11/14 10:58, Ian Campbell wrote: > Dropping netdev since this isn't relevant to them, adding Paul > > On Wed, 2014-11-05 at 10:50 +0000, David Vrabel wrote: >> - performance: Netback has already grant copied up-to 128 bytes from >> the first slot of a packet into the linear area. The first slot >> normally contain all the IPv4/IPv6 and TCP/UDP headers. > > Does "normally" here include guests other than Linux? I thought Windows > in particular was prone to splitting the headers into a frag per layer > or thereabouts? I'm not sure what guests Malcolm tested with. David