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Re: [E1000-devel] Transmission limit

To: sfeldma@xxxxxxxxx
Subject: Re: [E1000-devel] Transmission limit
From: Robert Olsson <Robert.Olsson@xxxxxxxxxxx>
Date: Wed, 1 Dec 2004 18:37:37 +0100
Cc: Robert Olsson <Robert.Olsson@xxxxxxxxxxx>, Lennert Buytenhek <buytenh@xxxxxxxxxxxxxx>, jamal <hadi@xxxxxxxxxx>, P@xxxxxxxxxxxxxx, mellia@xxxxxxxxxxxxxxxxxxxx, e1000-devel@xxxxxxxxxxxxxxxxxxxxx, Jorge Manuel Finochietto <jorge.finochietto@xxxxxxxxx>, Giulio Galante <galante@xxxxxxxxx>, netdev@xxxxxxxxxxx
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Scott Feldman writes:

 > Thank you Robert for trying it out.
 > 
 > Well those results are counter-intuitive!  We remove Tx interrupts and
 > Tx descriptor DMA write-backs and get no re-tries, and performance
 > drops?  The only bus activities left are the DMA of buffers to device
 > and the register writes to increment tail.  I'm stumped.  I'll need to
 > get my hands on a faster system.  Maybe there is a bus analyzer under
 > the tree.  :-)

 Huh. I've got a deja-vu feeling. What will happen if we remove almost all
 events (interrupts) and just have the timer waking up once-in-a-while?

                                                    --ro

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