From mboxrd@z Thu Jan 1 00:00:00 1970 From: Brian King Subject: Re: [patch 04/20] ibmveth: Add tx_copybreak Date: Thu, 19 Aug 2010 08:34:48 -0500 Message-ID: <4C6D32F8.1020409@linux.vnet.ibm.com> References: <20100819072456.317416634@samba.org> <20100819072503.937364037@samba.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Santiago Leon , netdev@vger.kernel.org To: Anton Blanchard Return-path: Received: from e1.ny.us.ibm.com ([32.97.182.141]:43732 "EHLO e1.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751166Ab0HSNe4 (ORCPT ); Thu, 19 Aug 2010 09:34:56 -0400 Received: from d01relay04.pok.ibm.com (d01relay04.pok.ibm.com [9.56.227.236]) by e1.ny.us.ibm.com (8.14.4/8.13.1) with ESMTP id o7JDSp4u030013 for ; Thu, 19 Aug 2010 09:28:51 -0400 Received: from d03av05.boulder.ibm.com (d03av05.boulder.ibm.com [9.17.195.85]) by d01relay04.pok.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id o7JDYtoC101282 for ; Thu, 19 Aug 2010 09:34:55 -0400 Received: from d03av05.boulder.ibm.com (loopback [127.0.0.1]) by d03av05.boulder.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id o7JDYsfL024665 for ; Thu, 19 Aug 2010 07:34:55 -0600 In-Reply-To: <20100819072503.937364037@samba.org> Sender: netdev-owner@vger.kernel.org List-ID: On 08/19/2010 02:25 AM, Anton Blanchard wrote: > Use the existing bounce buffer if we send a buffer under a certain size. > This saves the overhead of a TCE map/unmap. > > I can't see any reason for the wmb() in the bounce buffer case, if we need > a barrier it will be before we call h_send_logical_lan but we have > nothing in the common case. Remove it. > > Signed-off-by: Anton Blanchard > --- > > Index: powerpc.git/drivers/net/ibmveth.c > =================================================================== > --- powerpc.git.orig/drivers/net/ibmveth.c 2010-08-10 18:35:52.293272470 +1000 > +++ powerpc.git/drivers/net/ibmveth.c 2010-08-10 18:35:55.440741255 +1000 > @@ -117,6 +117,11 @@ MODULE_DESCRIPTION("IBM i/pSeries Virtua > MODULE_LICENSE("GPL"); > MODULE_VERSION(ibmveth_driver_version); > > +static unsigned int tx_copybreak __read_mostly = 128; Where did the 128 come from? I thought I heard the 2k value discussed in the past. Thanks, Brian -- Brian King Linux on Power Virtualization IBM Linux Technology Center