From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ben Greear Subject: Re: BCM5704 performance questions. Date: Fri, 10 Jun 2005 14:09:00 -0700 Message-ID: <42AA016C.9050801@candelatech.com> References: <42A8E0FE.3020708@candelatech.com> <1118361376.5838.20.camel@rh4> <42A8EBDA.6010306@candelatech.com> <1118363861.5838.29.camel@rh4> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Cc: "'netdev@oss.sgi.com'" Return-path: To: Michael Chan In-Reply-To: <1118363861.5838.29.camel@rh4> Sender: netdev-bounce@oss.sgi.com Errors-to: netdev-bounce@oss.sgi.com List-Id: netdev.vger.kernel.org Michael Chan wrote: > On Thu, 2005-06-09 at 18:24 -0700, Ben Greear wrote: > >>Michael Chan wrote: >> >>>Unfortunately, the 5704 requires the "ONE_DMA" workaround which will >>>limit throughput in a PCIX 100/133 bus. If you comment out the line that >>>sets the DMA_RWCTRL_ONE_DMA flag in tg3.c, you should see improved >>>performance. However, you may run into some DMA issues on certain >>>systems. >> >>Is there any way I can tell which systems are affected? It won't be >>an option for me to purposefully ship possibly busted drivers/hardware, >>but if I can be certain that my systems are immune, I will try this >>modification. >> > > I mentioned this so that you could verify that the slow performance was > indeed caused by ONE_DMA. Even if your system is affected, it's a very > subtle problem that won't show up right away and should allow you to get > some performance numbers. I commented out the code and ran the pktgen test again. It may be a small bit better, but not much: 770Mbps in one direction, 750Mbps in the other. Have you done any tests with 2 tg3 NICs in a single machine to see if they can run at or near line speed (full duplex)? Thanks, Ben -- Ben Greear Candela Technologies Inc http://www.candelatech.com