Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Thu, 5 Apr 2001 10:38:08 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Thu, 5 Apr 2001 10:37:58 -0400 Received: from quasar.osc.edu ([192.148.249.15]:199 "EHLO quasar.osc.edu") by vger.kernel.org with ESMTP id ; Thu, 5 Apr 2001 10:37:43 -0400 Date: Thu, 5 Apr 2001 10:36:41 -0400 From: Pete Wyckoff To: John Weidman Cc: linux-kernel@vger.kernel.org Subject: Re: Is jumbo ethernet MTU possible with Hamachi Gigabit ethernet driver? Message-ID: <20010405103641.B11386@quasar.osc.edu> In-Reply-To: <3ACBC361.CA701A2D@believe.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.3.16i-nntp2 In-Reply-To: <3ACBC361.CA701A2D@believe.com>; from johnw@believe.com on Wed, Apr 04, 2001 at 05:59:13PM -0700 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org The hardware also must support jumbo MTUs. Hamachi limit is 1518 or 1522 (vlan) bytes, and the driver can't fix that. -- Pete johnw@believe.com said: > I'm trying to get some Gigabit ethernet cards that use the Packet > Engines Hamachi GNIC-II chip to use a large mtu to attempt to get a > throughput of close to the 1Gb rating of the card. This is on a Compact > PCI Alpha system. I'm trying to use an MTU in the 8000 to 9000 range > and so far have not been able to get these MTUs to work. > > I have changed the PKT_BUF_SZ and MAX_FRAME_SIZE constants in hamachi.c > and ETH_DATA_LEN and ETH_FRAME_LEN in if_ether.h. I can use ifconfig to > change the MTU above 1500 on one side of a connection but as soon as I > raise the MTU on both sides to greater than 1500 the link dies. I can > change the MTU with ifconfig back to 1500 and the link will resume > operation. We are currently somewhat married to the 2.2.14 kernel. > > I read that some ethernet drivers will support jumbo MTUs. There > appears to be something in the hamachi driver or the kernel that I've > missed. Perhaps this only works with a later version kernel or the > hamachi driver needs more changes? Any help would be appreciated. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/