From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexander Duyck Subject: Re: [PATCH 1/4] e1000e: save skb counts in TX to avoid cache misses Date: Mon, 26 Apr 2010 08:55:06 -0700 Message-ID: <4BD5B75A.3040100@intel.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: "davem@davemloft.net" , "netdev@vger.kernel.org" To: Tom Herbert Return-path: Received: from mga01.intel.com ([192.55.52.88]:32726 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751323Ab0DZPzI (ORCPT ); Mon, 26 Apr 2010 11:55:08 -0400 In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: Tom Herbert wrote: > In e1000_tx_map, precompute number of segements and bytecounts which > are derived from fields in skb; these are stored in buffer_info. When > cleaning tx in e1000_clean_tx_irq use the values in the associated > buffer_info for statistics counting, this eliminates cache misses > on skb fields. > > Signed-off-by: Tom Herbert > --- > diff --git a/drivers/net/e1000e/e1000.h b/drivers/net/e1000e/e1000.h > index 12648a1..d6da75b 100644 > --- a/drivers/net/e1000e/e1000.h > +++ b/drivers/net/e1000e/e1000.h > @@ -188,6 +188,8 @@ struct e1000_buffer { > unsigned long time_stamp; > u16 length; > u16 next_to_watch; > + unsigned int segs; > + unsigned int bytecount; > u16 mapped_as_page; > }; > /* Rx */ Does segs need to be a full int here? I think you can probably get away with either an unsigned short or just define it as a u16, then combine it with mapped_as_page to cut down on the overall size. Thanks, Alex