public inbox for netdev@vger.kernel.org 
 help / color / mirror / Atom feed
From: hiren panchasara <hiren@strugglingcoder•info>
To: Yuchung Cheng <ycheng@google•com>
Cc: netdev <netdev@vger•kernel.org>, Neal Cardwell <ncardwell@google•com>
Subject: Re: A TLP implementation question
Date: Tue, 13 Feb 2018 23:39:58 -0800	[thread overview]
Message-ID: <20180214073958.GI28312@strugglingcoder.info> (raw)
In-Reply-To: <CAK6E8=cE5UmR7d9-cBftGBd9o7zvzZtCm_eOX=XdQjBe04d-eA@mail.gmail.com>

[-- Attachment #1: Type: text/plain, Size: 1157 bytes --]

On 02/13/18 at 05:11P, Yuchung Cheng wrote:
> On Tue, Feb 13, 2018 at 4:27 PM, hiren panchasara
> <hiren@strugglingcoder•info> wrote:
> >
> > Looking at current net-next to understand an aspect of TLP (tail loss
> > probe) implementation.
> >
> > https://tools.ietf.org/html/draft-ietf-tcpm-rack-02 is the source of
> > truth now for TLP and 6.2.1.  Phase 1: Scheduling a loss probe
> > Step 1: Check conditions for scheduling a PTO. has following as one of
> > the conditions:
> > (d) The most recently transmitted data was not itself a TLP probe
> > (i.e. a sender MUST NOT send consecutive TLP probes)
> this is done by
> 1) calling tcp_write_xmit(push_one==2) in tcp_send_loss_probe()
> 2) avoid calling tcp_schedule_loss_probe() if push_one == 2 in tcp_write_xmit()
> 3) abort if one TLP probe is inflight by checking tlp_high_seq in
> tcp-send_loss_probe()
> 
> consequently the sender will never schedule a PTO upon sending a probe
> (new or rtx) to avoid consecutive probes.
> 
> hth.

Thanks a lot, Yuchung! I was missing this simple and now obvious thing
of not scheduling a pto upon sending a tlp. :-)

Cheers,
Hiren

[-- Attachment #2: Type: application/pgp-signature, Size: 603 bytes --]

      reply	other threads:[~2018-02-14  7:39 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-02-14  0:27 A TLP implementation question hiren panchasara
2018-02-14  1:11 ` Yuchung Cheng
2018-02-14  7:39   ` hiren panchasara [this message]

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=20180214073958.GI28312@strugglingcoder.info \
    --to=hiren@strugglingcoder$(echo .)info \
    --cc=ncardwell@google$(echo .)com \
    --cc=netdev@vger$(echo .)kernel.org \
    --cc=ycheng@google$(echo .)com \
    /path/to/YOUR_REPLY

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