Development issues regarding the cerowrt test router project
 help / color / mirror / Atom feed
From: "David P. Reed" <dpreed@reed.com>
To: Sujith Manoharan <sujith@msujith.org>,Dave Taht <dave.taht@gmail.com>
Cc: "cerowrt-devel@lists.bufferbloat.net"
	<cerowrt-devel@lists.bufferbloat.net>
Subject: Re: [Cerowrt-devel] looking over ampdu stats
Date: Mon, 20 Jan 2014 07:09:04 -0800	[thread overview]
Message-ID: <0045e4e1-f1dd-4e15-81fb-4d616ffab08d@katmail.1gravity.com> (raw)
In-Reply-To: <21212.40503.163250.285305@gargle.gargle.HOWL>

[-- Attachment #1: Type: text/plain, Size: 1666 bytes --]

It's worth remembering that while aggregation of data in single units might reduce overhead, end to end latency is far more critical to most Internet apps.

Focusing on optimizing throughput for the last few percent in corner cases is NOT desirable.  In fact, it is the cause of pervasive buffer bloated designs, and the creator of "Daddy broke the Internet" scenarios.

Since LTE is badly configured in the field for Internet use, causing denial of service to many users because of bloated (multisecond to drain) queues, I would stop focusing on this, which is only a 10 percent issue.  Multisecond bloat is a disaster. You are fiddling while Rome burns imo.

On Jan 19, 2014, Sujith Manoharan <sujith@msujith.org> wrote:
>Dave Taht wrote:
>> Gotcha. I went later (at felix's urging) to look at the rc_stats
>> and that showed some decent averages for the actual number of
>> packets in the AMPDU. Never managed to get it much above 11,
>> regardless of what I set be_qlen to...
>
>Yes, something seems to be wrong.
>
>Using just 1 stream with iperf, the average A-MPDU length never
>goes above 10 and the throughput is about 90 Mbps.
>
>Using 4 iperf streams (using -P), the average A-MPDU length goes up to
>22
>and throughput reaches about 102 Mbps.
>
>This is with HT20. Using HT40 shows the behavior for 1 iperf stream.
>
>Sujith
>_______________________________________________
>Cerowrt-devel mailing list
>Cerowrt-devel@lists.bufferbloat.net
>https://lists.bufferbloat.net/listinfo/cerowrt-devel

-- 
Sent from my Android device with <a href=https://play.google.com/store/apps/details?id=com.onegravity.k10.pro2><b>K-@ Mail</b></a>. Please excuse my brevity.

[-- Attachment #2: Type: text/html, Size: 2173 bytes --]

  reply	other threads:[~2014-01-20 15:10 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-01-19 17:20 Dave Taht
2014-01-20  3:27 ` Sujith Manoharan
2014-01-20  3:38   ` Dave Taht
2014-01-20  3:55     ` Sujith Manoharan
2014-01-20 15:09       ` David P. Reed [this message]
2014-01-20 15:35         ` Sujith Manoharan

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

  List information: https://lists.bufferbloat.net/postorius/lists/cerowrt-devel.lists.bufferbloat.net/

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

  git send-email \
    --in-reply-to=0045e4e1-f1dd-4e15-81fb-4d616ffab08d@katmail.1gravity.com \
    --to=dpreed@reed.com \
    --cc=cerowrt-devel@lists.bufferbloat.net \
    --cc=dave.taht@gmail.com \
    --cc=sujith@msujith.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