Subject: Re: TSO on wm(4) (Intel Pro/1000): i82546 vs i8254EI vs others?
To: None <firstname.lastname@example.org, email@example.com,>
From: Jonathan Stone <firstname.lastname@example.org>
Date: 05/20/2005 18:03:05
In message <E1DZGPx-00054Wemail@example.com>,
Jonathan Stone writes:
>Without TSO, the 82544EI generates about 24,000 interrupts/sec at 123
>Mbyte/sec throughput, consuming about 50% CPU, with IPv4 and TCP
>checksum offload enabled. When I also enable TSO on the 82544EI, I
>see about about 17,000 interrupts/sec and from 40% to 45% CPU load --
>not much of a delta from the pre-TSO number, and very close to twice
>the CPU cost of filling just one 82546 channel.
>Are these results expected? Does anyone (Matt?) know how well TSO is
>supposed to work on the various versions of the Intel chip-- the CSA
>version, maybe? [...]
FWIW: I begged some time on an Intel 875P motherboard with CSA NIC.
There, `ifconfig wm0 tso4' works preety much as on the 82546.
I also tried three different 82544EI boards; all show the same behaviour.