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Re: BCM5704 performance questions.

To: Michael Chan <mchan@xxxxxxxxxxxx>
Subject: Re: BCM5704 performance questions.
From: Ben Greear <greearb@xxxxxxxxxxxxxxx>
Date: Fri, 10 Jun 2005 15:35:35 -0700
Cc: "'netdev@xxxxxxxxxxx'" <netdev@xxxxxxxxxxx>
In-reply-to: <1118438203.5294.7.camel@rh4>
Organization: Candela Technologies
References: <42A8E0FE.3020708@candelatech.com> <1118361376.5838.20.camel@rh4> <42A8EBDA.6010306@candelatech.com> <1118363861.5838.29.camel@rh4> <42AA016C.9050801@candelatech.com> <1118438203.5294.7.camel@rh4>
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Michael Chan wrote:
On Fri, 2005-06-10 at 14:09 -0700, Ben Greear wrote:

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.


The latest tg3 driver will print out the dma_rwctrl at probe time. Can
you check the value to make sure ONE_DMA is disabled? Bit 14 sets
ONE_DMA.

I don't see any printout in /var/log/messages that looks like it relates to the dma_rwctrl. I'm using the driver in 2.6.11..maybe it is not recent enough to print this information out?

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)?


Yes, we have years ago but not with the tg3 driver. We set up the 5704
to bridge (or route, I don't remember) one port to the other. It cannot
bridge at line-rate with the ONE_DMA workaround enabled.

Ok. Do you have other chipsets/NICs that can handle faster GigE speeds?

If you'd like to send me some multi-port NICs to play with I'll be happy
to report my findings :)

Thanks,
Ben

--
Ben Greear <greearb@xxxxxxxxxxxxxxx>
Candela Technologies Inc  http://www.candelatech.com


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