netdev.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: John Heffner <jheffner@psc.edu>
To: lists@andyfurniss.entadsl.com
Cc: netdev@vger.kernel.org
Subject: Re: Controlling TCP window size
Date: Tue, 16 May 2006 14:28:23 -0400	[thread overview]
Message-ID: <446A19C7.1000302@psc.edu> (raw)
In-Reply-To: <4469B251.3050901@andyfurniss.entadsl.com>

Andy Furniss wrote:
> 
> I've been doing some testing of my new wan connection and noticed that 
> when I specify a window with ip route it still changes after a while.

Looks like this is occurring in net/ipv4/tcp_input.c:tcp_rcv_space_adjust().

The problem really is that the window_clamp variable is overloaded. 
It's used as a kind of cache for rcvbuf -> window conversion, but also 
as a user-settable bound in window size.  On examination, it looks like 
this is also broken (in that window size won't increase) if a user does 
a setsockopt(SO_RCVBUF).  Can we make window_clamp a true clamp?  Then 
we can get rid of the hack of raising it in tcp_rcv_space_adjust().  I 
can cook up a patch if interested.

   -John

  reply	other threads:[~2006-05-16 18:28 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-05-16 11:06 Controlling TCP window size Andy Furniss
2006-05-16 18:28 ` John Heffner [this message]
2006-05-16 18:36   ` Andy Furniss
2006-05-16 18:48     ` John Heffner
2006-05-16 23:01   ` David S. Miller

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=446A19C7.1000302@psc.edu \
    --to=jheffner@psc.edu \
    --cc=lists@andyfurniss.entadsl.com \
    --cc=netdev@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).