Subject: Re: FW: Submission for S2io 10GbE driver

From: Andi Kleen <[email-masked]>
Date: Sat, 24 Jan 2004 15:58:09 +0100

On Fri, 23 Jan 2004 21:10:28 -0800
"Leonid Grossman" <[email-masked]> wrote:

> In Linux, there are couple performance issues that we see
> - transmit performance is noticeably worse than in Windows

In Linux 2.6 with TSO?

Other than that I would suggest to enable oprofile on 2.6 and post 
the profile numbers on the list.

> - checksum in 2.4 seems to be calculated by the host even if the device
> enables checksum offload

You have to use sendfile() for TX checksum off load. Without that the 
data needs to be copied anyways and a copy+csum is about the same cost
as a simple copy.

> - Large Send Offload in 2.6 (no LSO in 2.4) give much smaller boost
> comparing to Windows; on some systems there is no gain from LSO at all.

You mean TSO? Are you sure the test programs submitted big enough 
buffers to the TCP stack?

-Andi