From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tom Herbert Subject: Re: Receive steering and hash and cache misses Date: Fri, 2 Apr 2010 10:59:43 -0700 Message-ID: References: <20100402102650.5bdb5b52@nehalam> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Eric Dumazet , netdev@vger.kernel.org To: Stephen Hemminger Return-path: Received: from smtp-out.google.com ([74.125.121.35]:34010 "EHLO smtp-out.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755861Ab0DBR7r convert rfc822-to-8bit (ORCPT ); Fri, 2 Apr 2010 13:59:47 -0400 Received: from wpaz1.hot.corp.google.com (wpaz1.hot.corp.google.com [172.24.198.65]) by smtp-out.google.com with ESMTP id o32HxjNl013579 for ; Fri, 2 Apr 2010 19:59:45 +0200 Received: from gyd12 (gyd12.prod.google.com [10.243.49.204]) by wpaz1.hot.corp.google.com with ESMTP id o32Hxh3r002809 for ; Fri, 2 Apr 2010 10:59:44 -0700 Received: by gyd12 with SMTP id 12so1003874gyd.16 for ; Fri, 02 Apr 2010 10:59:43 -0700 (PDT) In-Reply-To: <20100402102650.5bdb5b52@nehalam> Sender: netdev-owner@vger.kernel.org List-ID: On Fri, Apr 2, 2010 at 10:26 AM, Stephen Hemminger wrote: > > Although Receive Packet Steering can use a hardware generated receive= hash > the device driver still causes an unnecessary cache miss on the inter= rupt > processing CPU. =A0The current Ethernet network device driver receive= processing > has the device driver calling eth_type_trans() which causes a the > interrupt CPU to read the received frame header. > 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 getting rxhash from bnx2x which does this. > Is there some way the hardware receive hash value could be used to > steer to the receive CPU, then have the receive CPU find the Ethernet > type field (eth_type_trans)? > -- > To unsubscribe from this list: send the line "unsubscribe netdev" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at =A0http://vger.kernel.org/majordomo-info.html