All of lore.kernel.org
 help / color / mirror / Atom feed
From: Eric Dumazet <eric.dumazet@gmail.com>
To: "Francis Y. Yan" <francisyyan@gmail.com>
Cc: davem@davemloft.net, netdev@vger.kernel.org, edumazet@google.com,
	soheil@google.com, ncardwell@google.com,
	Yuchung Cheng <ycheng@google.com>
Subject: Re: [PATCH net-next 1/2] tcp: measure rwnd-limited time
Date: Wed, 07 Sep 2016 07:19:16 -0700	[thread overview]
Message-ID: <1473257956.10725.26.camel@edumazet-glaptop3.roam.corp.google.com> (raw)
In-Reply-To: <1473211961-107223-1-git-send-email-francisyyan@gmail.com>

On Tue, 2016-09-06 at 18:32 -0700, Francis Y. Yan wrote:
> This patch measures the total time when TCP transmission is limited
> by receiver's advertised window (rwnd), and exports it in tcp_info as
> tcpi_rwnd_limited.
> 
> The rwnd-limited time is defined as the period when the next segment
> to send by TCP cannot fit into rwnd. To measure it, we record the last
> timestamp when limited by rwnd (rwnd_limited_ts) and the total
> rwnd-limited time (rwnd_limited) in tcp_sock.
> 
> Then we export the total rwnd-limited time so far in tcp_info, where
> by so far, we mean that if TCP transmission is still being limited by
> rwnd, the time interval since rwnd_limited_ts needs to be counted as
> well; otherwise, we simply export rwnd_limited.
> 
> It is worth noting that we also have to add a new sequence counter
> (seqcnt) in tcp_sock to carefully handle tcp_info's reading of
> rwnd_limited_ts and rwnd_limited in order to get a consistent snapshot
> of both variables together.
> 
> Signed-off-by: Francis Y. Yan <francisyyan@gmail.com>
> Signed-off-by: Yuchung Cheng <ycheng@google.com>
> ---

Acked-by: Eric Dumazet <edumazet@google.com>

Thanks Francis !

  parent reply	other threads:[~2016-09-07 14:19 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-09-07  1:32 [PATCH net-next 1/2] tcp: measure rwnd-limited time Francis Y. Yan
2016-09-07  1:32 ` [PATCH net-next 2/2] tcp: put a TLV list of TCP stats in error queue Francis Y. Yan
2016-09-07  5:04   ` Soheil Hassas Yeganeh
2016-09-07 14:22   ` Eric Dumazet
2016-09-07  5:07 ` [PATCH net-next 1/2] tcp: measure rwnd-limited time Soheil Hassas Yeganeh
2016-09-07 14:19 ` Eric Dumazet [this message]
2016-09-08  0:27 ` David Miller
2016-09-08 15:31   ` Yuchung Cheng

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=1473257956.10725.26.camel@edumazet-glaptop3.roam.corp.google.com \
    --to=eric.dumazet@gmail.com \
    --cc=davem@davemloft.net \
    --cc=edumazet@google.com \
    --cc=francisyyan@gmail.com \
    --cc=ncardwell@google.com \
    --cc=netdev@vger.kernel.org \
    --cc=soheil@google.com \
    --cc=ycheng@google.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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.