Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Tue, 27 Aug 2002 14:23:32 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Tue, 27 Aug 2002 14:23:32 -0400 Received: from elin.scali.no ([62.70.89.10]:5650 "EHLO elin.scali.no") by vger.kernel.org with ESMTP id ; Tue, 27 Aug 2002 14:23:31 -0400 Date: Tue, 27 Aug 2002 20:22:03 +0200 (CEST) From: Steffen Persvold X-X-Sender: sp@sp-laptop.isdn.scali.no To: linux-kernel@vger.kernel.org Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3307 Lines: 95 Dear list people, Lately I've been testing out a couple of Dell PowerEdge 2650 machines. These babies have dual onboard BCM95701A10 NICs (Tigon3 chip) mounted in the same PCI-X 133MHz 64 bit bus. Since they have dual onboard GbE, I've been trying to channel bond them using just two crossover cables between two machines. The results I'm seeing is at the first glance very strange. What I see is that the performance when bonded (round robin) is about _half_ (and sometimes even less) compared to just using a single interface. Here are some netpipe-2.4 results : 64k message size, single interface 1: 65536 bytes 190 times --> 760.54 Mbps in 0.000657 sec 256k message size, single interface 1: 262144 bytes 53 times --> 855.04 Mbps in 0.002339 sec 64 message size, both interfaces (using round robin) 1: 65536 bytes 65 times --> 257.06 Mbps in 0.001945 sec 256k message size, both interfaces (using round robin) 1: 262144 bytes 25 times --> 376.01 Mbps in 0.005319 sec Looking at the output of netstat -s after a testrun with 256k message size, I see some differences (main items) : Single interface : Tcp: 0 segments retransmited TcpExt: 109616 packets directly queued to recvmsg prequeue. 52249581 packets directly received from backlog 125694404 packets directly received from prequeue 78 packets header predicted 124999 packets header predicted and directly queued to user TCPPureAcks: 93 TCPHPAcks: 22981 Bonded interfaces : Tcp: 234 segments retransmited TcpExt: 1 delayed acks sent Quick ack mode was activated 234 times 67087 packets directly queued to recvmsg prequeue. 6058227 packets directly received from backlog 13276665 packets directly received from prequeue 6232 packets header predicted 4625 packets header predicted and directly queued to user TCPPureAcks: 25708 TCPHPAcks: 4456 The biggest difference as far as I can see is the 'packtes header predicted', 'packets header predicted and directly queued to user', 'TCPPureAcks' and TCPHPAcks. I have an idea that this happens because the packets are comming out of order into the receiving node (i.e the bonding device is alternating between each interface when sending, and when the receiving node gets the packets it is possible that the first interface get packets number 0, 2, 4 and 6 in one interrupt and queues it to the network stack before packet 1, 3, 5 is handled on the other interface). If this is the case, any ideas how to fix this... I would really love to get 2Gbit/sec on these machines.... PS I've also seen this feature on the Intel GbE cards (e1000), but these drivers has a parameter named RxIntDelay which can be set to 0 to get interrupt for each packet. Is this possible with the tg3 driver too ? DS Regards, -- Steffen Persvold | Scali AS mailto:sp@scali.com | http://www.scali.com Tel: (+47) 2262 8950 | Olaf Helsets vei 6 Fax: (+47) 2262 8951 | N0621 Oslo, NORWAY - 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/