From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754861Ab0IORl7 (ORCPT ); Wed, 15 Sep 2010 13:41:59 -0400 Received: from mail.perches.com ([173.55.12.10]:2066 "EHLO mail.perches.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753847Ab0IORl6 (ORCPT ); Wed, 15 Sep 2010 13:41:58 -0400 Subject: [RFC PATCH] drivers/net/tg3.c: Raise Jumbo Frame MTU to 9216? From: Joe Perches To: Matt Carlson , Michael Chan , Benjamin Li Cc: "David S. Miller" , netdev , LKML Content-Type: text/plain; charset="UTF-8" Date: Wed, 15 Sep 2010 10:41:56 -0700 Message-ID: <1284572516.10223.12.camel@Joe-Laptop> Mime-Version: 1.0 X-Mailer: Evolution 2.30.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The TG3 apparently supports 9K frame sizes. http://www.broadcom.com/collateral/pb/5704C-PB05-R.pdf Is exactly 9000 a hardware limit? Should the jumbo frame MTU be raised to 9216 or 9216 less the size of MAC, VLAN, IP and TCP headers? diff --git a/drivers/net/tg3.c b/drivers/net/tg3.c index 9f6ffff..3727070 100644 --- a/drivers/net/tg3.c +++ b/drivers/net/tg3.c @@ -95,7 +95,7 @@ /* hardware minimum and maximum for a single frame's data payload */ #define TG3_MIN_MTU 60 #define TG3_MAX_MTU(tp) \ - ((tp->tg3_flags & TG3_FLAG_JUMBO_CAPABLE) ? 9000 : 1500) + ((tp->tg3_flags & TG3_FLAG_JUMBO_CAPABLE) ? 9216 : 1500) /* These numbers seem to be hard coded in the NIC firmware somehow. * You can't change the ring sizes, but you can change where you place