From mboxrd@z Thu Jan 1 00:00:00 1970 From: Robert Jennings Subject: [PATCH] ibmveth: Increase default copybreak limits to 2k Date: Thu, 21 Oct 2010 09:37:53 -0500 Message-ID: <20101021143753.GA5567@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: netdev@vger.kernel.org To: David Miller Return-path: Received: from e31.co.us.ibm.com ([32.97.110.149]:39620 "EHLO e31.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751080Ab0JUOhz (ORCPT ); Thu, 21 Oct 2010 10:37:55 -0400 Received: from d03relay03.boulder.ibm.com (d03relay03.boulder.ibm.com [9.17.195.228]) by e31.co.us.ibm.com (8.14.4/8.13.1) with ESMTP id o9LEP7A7002525 for ; Thu, 21 Oct 2010 08:25:07 -0600 Received: from d03av06.boulder.ibm.com (d03av06.boulder.ibm.com [9.17.195.245]) by d03relay03.boulder.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id o9LEbspU186542 for ; Thu, 21 Oct 2010 08:37:54 -0600 Received: from d03av06.boulder.ibm.com (loopback [127.0.0.1]) by d03av06.boulder.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id o9LEfmQc024689 for ; Thu, 21 Oct 2010 08:41:48 -0600 Content-Disposition: inline Sender: netdev-owner@vger.kernel.org List-ID: Increase the copybreak limits for rx and tx from 128 bytes to 2048 bytes. These limits were added by commits 8d86c61ae41d9068fd5e5cc01a4abd53c4fe3ab5 and c08cc3ccebd46dce44d13a8ce81d249e687eeb8a to make use of a bounce buffer for packets below 128 bytes. This avoids tearing down and creating a TCE entry. Performance testing shows that this default limit can be increased from 128 to 2048 for both rx and tx copybreak. This resulted in ~10% throughput increase for for packets that fit this limit without affecting performance for larger packets. Signed-off-by: Robert Jennings --- drivers/net/ibmveth.c | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/net/ibmveth.c b/drivers/net/ibmveth.c index c454b45..20b7a98 100644 --- a/drivers/net/ibmveth.c +++ b/drivers/net/ibmveth.c @@ -65,12 +65,12 @@ MODULE_DESCRIPTION("IBM Power Virtual Ethernet Driver"); MODULE_LICENSE("GPL"); MODULE_VERSION(ibmveth_driver_version); -static unsigned int tx_copybreak __read_mostly = 128; +static unsigned int tx_copybreak __read_mostly = 2048; module_param(tx_copybreak, uint, 0644); MODULE_PARM_DESC(tx_copybreak, "Maximum size of packet that is copied to a new buffer on transmit"); -static unsigned int rx_copybreak __read_mostly = 128; +static unsigned int rx_copybreak __read_mostly = 2048; module_param(rx_copybreak, uint, 0644); MODULE_PARM_DESC(rx_copybreak, "Maximum size of packet that is copied to a new buffer on receive"); -- 1.7.0.4