Date: Thu, 27 Jan 2005 16:57:07 -0800
From: "David S. Miller" <davem@davemloft.net>
To: Rick Jones <rick.jones2@hp.com>
Cc: netdev@oss.sgi.com
Subject: Re: on the wire behaviour of TSO on/off is supposed to be the same
 yes?
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On Thu, 27 Jan 2005 16:10:46 -0800
Rick Jones <rick.jones2@hp.com> wrote:


> The other relates to the business of disabling TSO on a connection upon packet loss.

There cannot possibly any compliance issues resulting from turning
off an optimization in the face of packet loss.

> Internet connected systems experience non-trivial packet loss rates and so if TSO 
> disabled upon packet loss it means a given benchmark result using TSO deviates 
> even more from reality than one without TSO.

And running the benchmark over a local gigabit subnet doesn't deviate
from what Internet connected systems can expect to achieve how-so?

Oh you mean I really can get 60,000 web or database connections a second
when the users are over modems half-way across the planet?  Give me a
break...

Furthermore, all the tuning people do in each run is to optimize
specifically for a local high-speed interconnect subnet, no limits
on TCP or filesystem memory use, and large cache sizes.  Nobody
configures their machines this way, unless they want remote users
to be able to consume %90 or so of their system memory with TCP
socket memory.

Anyways, see my other posting, we'll be able to keep TSO enabled in
the face of packet loss, but that is an optimization not a correctness
fix.