Netdev List
 help / color / mirror / Atom feed
From: David Miller <davem@davemloft.net>
To: yinglin.s@gmail.com
Cc: netdev@vger.kernel.org
Subject: Re: [TCP_CA_CWR] Causes for entering TCP_CA_CWR state with 0 retransmissions
Date: Tue, 14 Jul 2009 11:42:11 -0700 (PDT)	[thread overview]
Message-ID: <20090714.114211.254914419.davem@davemloft.net> (raw)
In-Reply-To: <46bf9ede0907141138q3b665aefv46a18591c3cfc2ce@mail.gmail.com>

From: Yinglin Sun <yinglin.s@gmail.com>
Date: Tue, 14 Jul 2009 14:38:07 -0400

> I have a question about tcp_ca_state "TCP_CA_CWR".  Under what
> circumstances does it enter this state?
> I'm doing some experiments and have trace from tcp_info. From tcp_info
> trace, I found that many places show ca_state is 2 (TCP_CA_CWR). Under
> this state, the congestion window size decreases but the total number
> of retransmissions is still 0.

What kind of "retransmissions"?  I bet the counter you are looking
at is counting timeout based retransmissions, which means it isn't
including the most predominant type of retransmissions, which are
fast retransmissions which are triggered in response to ACKs.

  reply	other threads:[~2009-07-14 18:42 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-07-14 18:38 [TCP_CA_CWR] Causes for entering TCP_CA_CWR state with 0 retransmissions Yinglin Sun
2009-07-14 18:42 ` David Miller [this message]
2009-07-14 19:12   ` Yinglin Sun
2009-07-14 19:15     ` David Miller
2009-07-14 19:49       ` Yinglin Sun
2009-07-14 19:53         ` David Miller
2009-07-14 19:58           ` Yinglin Sun

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=20090714.114211.254914419.davem@davemloft.net \
    --to=davem@davemloft.net \
    --cc=netdev@vger.kernel.org \
    --cc=yinglin.s@gmail.com \
    /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