From: "Scott M. Ferris" <sferris@acm.org>
To: "David S. Miller" <davem@davemloft.net>
Cc: "Scott M. Ferris" <sferris@acm.org>, netdev@oss.sgi.com
Subject: Re: TSO prevents cwnd growth on 2.6 kernels
Date: Fri, 25 Mar 2005 13:34:59 -0600 [thread overview]
Message-ID: <20050325193458.GA15645@visi.com> (raw)
In-Reply-To: <20050325104000.713229be.davem@davemloft.net>
On Fri, Mar 25, 2005 at 10:40:00AM -0800, David S. Miller wrote:
>
> We know it's busted. I haven't gotten to fixing this stuff
> up yet.
Perhaps TSO should default to off for all drivers then? I hadn't even
noticed it was enabled until after I was debugging the problem.
> Are you suggesting to let it go past tp->snd_cwnd? We can't
> ever do that. tp->snd_cwnd is a hard limit on the number
> of frames we may have outstanding on the network at one time,
> TSO or not.
No, I think we all agree that exceeding cwnd is a bad idea. I'm just
saying that failing to reach cwnd is also broken, especially if it
results in tcp_write_xmit() sending nothing at all when cwnd is small.
--
Scott M. Ferris,
sferris@acm.org
next prev parent reply other threads:[~2005-03-25 19:34 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-03-25 18:18 TSO prevents cwnd growth on 2.6 kernels Scott M. Ferris
2005-03-25 18:40 ` David S. Miller
2005-03-25 19:34 ` Scott M. Ferris [this message]
2005-03-25 19:40 ` David S. Miller
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