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Re: FW: Submission for S2io 10GbE driver

To: "Leonid Grossman" <leonid.grossman@xxxxxxxx>
Subject: Re: FW: Submission for S2io 10GbE driver
From: Andi Kleen <ak@xxxxxxx>
Date: Sat, 24 Jan 2004 15:58:09 +0100
Cc: hadi@xxxxxxxxxx, netdev@xxxxxxxxxxx
In-reply-to: <000001c3e238$62efbb30$0400a8c0@xxxxxxxxxxxx>
References: <1074914062.1036.39.camel@xxxxxxxxxxxxxxxx> <000001c3e238$62efbb30$0400a8c0@xxxxxxxxxxxx>
Sender: netdev-bounce@xxxxxxxxxxx
On Fri, 23 Jan 2004 21:10:28 -0800
"Leonid Grossman" <leonid.grossman@xxxxxxxx> 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

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