From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael Chan" Subject: Re: BCM5704 performance questions. Date: Thu, 09 Jun 2005 17:37:41 -0700 Message-ID: <1118363861.5838.29.camel@rh4> References: <42A8E0FE.3020708@candelatech.com> <1118361376.5838.20.camel@rh4> <42A8EBDA.6010306@candelatech.com> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Cc: "'netdev@oss.sgi.com'" Return-path: To: "Ben Greear" In-Reply-To: <42A8EBDA.6010306@candelatech.com> Sender: netdev-bounce@oss.sgi.com Errors-to: netdev-bounce@oss.sgi.com List-Id: netdev.vger.kernel.org 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. Unfortunately, if indeed it is ONE_DMA, there is no easy way for us to tell which system is affected. And the recommendation is to turn it on for all 5704 in PCIX 100/133.