From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Kirsher Subject: [net-next-2.6 PATCH 1/4] e1000e: save skb counts in TX to avoid cache misses Date: Wed, 05 May 2010 17:02:27 -0700 Message-ID: <20100506000221.8042.64794.stgit@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, gospo@redhat.com, Tom Herbert , Bruce Allan , Jeff Kirsher To: davem@davemloft.net Return-path: Received: from qmta12.emeryville.ca.mail.comcast.net ([76.96.27.227]:35901 "EHLO qmta12.emeryville.ca.mail.comcast.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751349Ab0EFACr (ORCPT ); Wed, 5 May 2010 20:02:47 -0400 Sender: netdev-owner@vger.kernel.org List-ID: From: Tom Herbert 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 Acked-by: Bruce Allan Signed-off-by: Jeff Kirsher --- drivers/net/e1000e/e1000.h | 2 ++ drivers/net/e1000e/netdev.c | 18 +++++++++--------- 2 files changed, 11 insertions(+), 9 deletions(-) diff --git a/drivers/net/e1000e/e1000.h b/drivers/net/e1000e/e1000.h index 906c4da..c0b3db4 100644 --- a/drivers/net/e1000e/e1000.h +++ b/drivers/net/e1000e/e1000.h @@ -189,6 +189,8 @@ struct e1000_buffer { unsigned long time_stamp; u16 length; u16 next_to_watch; + unsigned int segs; + unsigned int bytecount; u16 mapped_as_page; }; /* Rx */ diff --git a/drivers/net/e1000e/netdev.c b/drivers/net/e1000e/netdev.c index 0a16465..1eb9b59 100644 --- a/drivers/net/e1000e/netdev.c +++ b/drivers/net/e1000e/netdev.c @@ -1001,14 +1001,8 @@ static bool e1000_clean_tx_irq(struct e1000_adapter *adapter) cleaned = (i == eop); if (cleaned) { - struct sk_buff *skb = buffer_info->skb; - unsigned int segs, bytecount; - segs = skb_shinfo(skb)->gso_segs ?: 1; - /* multiply data chunks by size of headers */ - bytecount = ((segs - 1) * skb_headlen(skb)) + - skb->len; - total_tx_packets += segs; - total_tx_bytes += bytecount; + total_tx_packets += buffer_info->segs; + total_tx_bytes += buffer_info->bytecount; } e1000_put_txbuf(adapter, buffer_info); @@ -4277,7 +4271,7 @@ static int e1000_tx_map(struct e1000_adapter *adapter, struct e1000_buffer *buffer_info; unsigned int len = skb_headlen(skb); unsigned int offset = 0, size, count = 0, i; - unsigned int f; + unsigned int f, bytecount, segs; i = tx_ring->next_to_use; @@ -4337,7 +4331,13 @@ static int e1000_tx_map(struct e1000_adapter *adapter, } } + segs = skb_shinfo(skb)->gso_segs ?: 1; + /* multiply data chunks by size of headers */ + bytecount = ((segs - 1) * skb_headlen(skb)) + skb->len; + tx_ring->buffer_info[i].skb = skb; + tx_ring->buffer_info[i].segs = segs; + tx_ring->buffer_info[i].bytecount = bytecount; tx_ring->buffer_info[first].next_to_watch = i; return count;