From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Hemminger Subject: Re: Receive steering and hash and cache misses Date: Fri, 2 Apr 2010 11:54:39 -0700 Message-ID: <20100402115439.348575c9@nehalam> References: <20100402102650.5bdb5b52@nehalam> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Eric Dumazet , netdev@vger.kernel.org To: Tom Herbert Return-path: Received: from mail.vyatta.com ([76.74.103.46]:47008 "EHLO mail.vyatta.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752643Ab0DBTBE convert rfc822-to-8bit (ORCPT ); Fri, 2 Apr 2010 15:01:04 -0400 In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: On Fri, 2 Apr 2010 10:59:43 -0700 Tom Herbert wrote: > On Fri, Apr 2, 2010 at 10:26 AM, Stephen Hemminger > wrote: > > > > Although Receive Packet Steering can use a hardware generated recei= ve hash > > the device driver still causes an unnecessary cache miss on the int= errupt > > processing CPU. =C2=A0The current Ethernet network device driver re= ceive processing > > has the device driver calling eth_type_trans() which causes a the > > interrupt CPU to read the received frame header. > > >=20 > It should be possible to deduce the values set by eth_type_trans from > the RX descriptor along with the RX hash. I'll post the patch gettin= g > rxhash from bnx2x which does this. >=20 On sky2, I get only RSS, Checksum, and length from descriptor info.