From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754686AbcHXRPw (ORCPT ); Wed, 24 Aug 2016 13:15:52 -0400 Received: from mail-pf0-f195.google.com ([209.85.192.195]:35641 "EHLO mail-pf0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752765AbcHXRPs (ORCPT ); Wed, 24 Aug 2016 13:15:48 -0400 Subject: Re: [PATCH 3/3] net: fs_enet: make rx_copybreak value configurable To: Christophe Leroy , Pantelis Antoniou , Vitaly Bordug , davem@davemloft.net References: <0609ecd8fa7ecaa99a386e17f47027349cc3fdda.1472033140.git.christophe.leroy@c-s.fr> Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, netdev@vger.kernel.org From: Florian Fainelli Message-ID: Date: Wed, 24 Aug 2016 10:14:16 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.2.0 MIME-Version: 1.0 In-Reply-To: <0609ecd8fa7ecaa99a386e17f47027349cc3fdda.1472033140.git.christophe.leroy@c-s.fr> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 08/24/2016 03:36 AM, Christophe Leroy wrote: > Measurement shows that on a MPC8xx running at 132MHz, the optimal > limit is 112: > * 114 bytes packets are processed in 147 TB ticks with higher copybreak > * 114 bytes packets are processed in 148 TB ticks with lower copybreak > * 128 bytes packets are processed in 154 TB ticks with higher copybreak > * 128 bytes packets are processed in 148 TB ticks with lower copybreak > * 238 bytes packets are processed in 172 TB ticks with higher copybreak > * 238 bytes packets are processed in 148 TB ticks with lower copybreak > > However it might be different on other processors > and/or frequencies. So it is useful to make it configurable. > > Signed-off-by: Christophe Leroy > --- > drivers/net/ethernet/freescale/fs_enet/fs_enet-main.c | 8 +++++--- > include/linux/fs_enet_pd.h | 1 - > 2 files changed, 5 insertions(+), 4 deletions(-) > > diff --git a/drivers/net/ethernet/freescale/fs_enet/fs_enet-main.c b/drivers/net/ethernet/freescale/fs_enet/fs_enet-main.c > index addcae6..b59bbf8 100644 > --- a/drivers/net/ethernet/freescale/fs_enet/fs_enet-main.c > +++ b/drivers/net/ethernet/freescale/fs_enet/fs_enet-main.c > @@ -60,6 +60,10 @@ module_param(fs_enet_debug, int, 0); > MODULE_PARM_DESC(fs_enet_debug, > "Freescale bitmapped debugging message enable value"); > > +static int rx_copybreak = 240; > +module_param(rx_copybreak, int, S_IRUGO | S_IWUSR); > +MODULE_PARM_DESC(rx_copybreak, "Receive copy threshold"); There is an ethtool tunable knob for copybreak now, which you should prefer over a module parameter, see drivers/net/ethernet/cisco/enic/enic_ethtool.c -- Florian