Re: Throughput riddle

From	"John L. Ries" <jries@salford-systems.com>
Newsgroups	linux.debian.user
Subject	Re: Throughput riddle
Date	2016-03-18 19:50 +0100
Message-ID	<re7Db-4UD-1@gated-at.bofh.it> (permalink)
References	<re5L5-23u-39@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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I don't know if it will help, but I hook up my Iomega NAS directly to my 
desktop machine with a regular cat 5/6 cable (each has two gigabit 
Ethernet ports, so each can connect to the rest of my network, as well 
as to each other) and that seems to help the throughput by a lot (but I 
don't have any numbers for you).  So if your NAS has an extra Ethernet 
port, you might want to hook it up to your laptop when you're in the 
same room with it and use your wifi interface to connect to your 
network.  Certainly, you should avoid connecting to your NAS over wifi 
if you're using it heavily, as that will definitely slow things down (it 
seems that a lot more handshaking is required to connect through the air 
than through a physical cable).

--------------------------|
John L. Ries              |
Salford Systems           |
Phone: (619)543-8880 x107 |
or     (435)867-8885      |
--------------------------|


On Friday 2016-03-18 10:48, Celejar wrote:

>Date: Fri, 18 Mar 2016 10:48:24
>From: Celejar <celejar@gmail.com>
>To: debian-user <debian-user@lists.debian.org>
>Subject: Throughput riddle
>
> Hi,
>
> I'm trying to understand the throughput across the different links of
> my little home network, and am perplexed by the measured wireless
> throughput.
>
> The three main devices I'm interested in:
>
> Router: Buffalo WZR-HP-G300NH running OpenWrt (Chaos Calmer 15.05).
> Gigabit WAN and LAN, 802.11bgn wireless.
>
> https://wiki.openwrt.org/toh/buffalo/wzr-hp-g300h
>
> Laptop: Thinkpad T61 running Jessie 8.3. Gigabit ethernet, 802.11abgn
> wireless.
>
> NAS: Seagate GoFlex Net [STAK100] runninng Debian Jessie 8.3.
>
> https://archlinuxarm.org/platforms/armv5/seagate-goflex-net
>
> All throughput measurements taken with iperf (run three times and using
> the median result), unless specified otherwise. These first results are
> with the laptop connected to the router via cat5:
>
> Laptop - NAS:		~874 Mbps.
>
> I suppose this is close enough to the gigabit theoretical max, and there isn't
> any significant bottleneck.
>
> Router - NAS:		~217 Mbps
> Router - laptop:	~198 Mbps
>
> Here the router CPU is apparently the bottleneck (top shows close to
> 100% CPU utilization by iperf for at least part of the 10 second iperf
> runs). I suppose that this is due to the bits needing to be copied out
> of the kernel networking stack into iperf's userspace memory, or
> something like that. I don't understanding why the NAS seems to be
> doing better, but I suppose it could be an artifact of the data.
>
> Here's the part that baffles me - these are with the laptop connected
> to the router wirelessly:
>
> Laptop - router:	~11.8 Mbps
>
> These numbers actually exhibit significant variance, but they're
> generally at least this much, and at most about 15-20 Mbps.
>
> Laptop - NAS:		~14.7 Mbps
>
> Once again, these numbers vary widely, but are in line with the laptop
> - router numbers.
>
> But here's the kicker: Ookla's speedtest (run on the laptop with
> speedtest-cli) shows 29.01/5.89 (d/u), and this is fairly consistent.
> I'm paying Comcast for 25/5, and they apparently provision at
> 31.25/6.25, so I'm getting quite close to the theoretical max, even
> when the laptop is connected to the router wirelessly. Additionally,
> various Android phones also get close to the Comcast provisioned max
> when connecting wirelessly to the router.
>
> So the wireless link can apparently push at least 30 Mbps or so, so why
> are my local wireless throughput numbers so much lower?
>
> I was originally using one of the common 1/6/11 channels, and I switched
> to 3 since I saw a lot of other stations on those channels. This may
> have resulted in some improvement, but I'm still stuck locally as
> above. What's the explanation for this - how can I possibly be getting
> much better throughput to servers tens of miles away than to my local
> stations? Does iperf somehow work fundamentally differently from
> speedtest? If so, which is a better representation of actual throughput?
>
> Celejar
>
>

Thread

Throughput riddle Celejar <celejar@gmail.com> - 2016-03-18 17:50 +0100
  Re: Throughput riddle "John L. Ries" <jries@salford-systems.com> - 2016-03-18 19:50 +0100
    Re: Throughput riddle "John L. Ries" <jries@salford-systems.com> - 2016-03-18 20:30 +0100
      Re: Throughput riddle Celejar <celejar@gmail.com> - 2016-03-18 20:40 +0100
    Re: Throughput riddle Celejar <celejar@gmail.com> - 2016-03-18 20:40 +0100
  Re: Throughput riddle David Christensen <dpchrist@holgerdanske.com> - 2016-03-19 02:10 +0100
    Re: Throughput riddle Richard Hector <richard@walnut.gen.nz> - 2016-03-19 02:50 +0100
      Re: Throughput riddle David Christensen <dpchrist@holgerdanske.com> - 2016-03-19 03:10 +0100
        Re: Throughput riddle Richard Hector <richard@walnut.gen.nz> - 2016-03-19 03:50 +0100
          Re: Throughput riddle David Christensen <dpchrist@holgerdanske.com> - 2016-03-19 04:50 +0100
          Re: Throughput riddle Celejar <celejar@gmail.com> - 2016-03-20 14:20 +0100
    Re: Throughput riddle Celejar <celejar@gmail.com> - 2016-03-20 14:20 +0100
      Re: Throughput riddle David Christensen <dpchrist@holgerdanske.com> - 2016-03-20 17:40 +0100
        Re: Throughput riddle Celejar <celejar@gmail.com> - 2016-03-20 19:10 +0100
          Re: Throughput riddle David Christensen <dpchrist@holgerdanske.com> - 2016-03-20 21:50 +0100
            Re: Throughput riddle Celejar <celejar@gmail.com> - 2016-03-21 03:20 +0100
              Re: Throughput riddle David Christensen <dpchrist@holgerdanske.com> - 2016-03-21 06:00 +0100
                Re: Throughput riddle Celejar <celejar@gmail.com> - 2016-03-22 05:30 +0100
                Re: Throughput riddle David Christensen <dpchrist@holgerdanske.com> - 2016-03-24 02:50 +0100
                Re: Throughput riddle Celejar <celejar@gmail.com> - 2016-03-24 04:10 +0100
  Re: Throughput riddle arian <debian@semioptimal.net> - 2016-03-20 14:50 +0100
    Re: Throughput riddle Celejar <celejar@gmail.com> - 2016-03-20 15:50 +0100
      Re: Throughput riddle arian <debian@semioptimal.net> - 2016-03-20 16:30 +0100
        Re: Throughput riddle Celejar <celejar@gmail.com> - 2016-03-20 18:40 +0100
        Re: Throughput riddle Andrew McGlashan <andrew.mcglashan@affinityvision.com.au> - 2016-03-20 19:50 +0100
  RE: Throughput riddle Bonno Bloksma <b.bloksma@tio.nl> - 2016-03-21 12:50 +0100
    Re: Throughput riddle Celejar <celejar@gmail.com> - 2016-03-22 05:40 +0100
  Re: Throughput riddle Dan Purgert <dan@djph.net> - 2016-03-21 13:30 +0100
    Re: Throughput riddle Celejar <celejar@gmail.com> - 2016-03-22 05:50 +0100
      Re: Throughput riddle David <david.g_jones@ntlworld.com> - 2016-03-22 11:20 +0100
        RE: Throughput riddle Bonno Bloksma <b.bloksma@tio.nl> - 2016-03-22 13:40 +0100

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