[K12OSN] Where is the bottleneck?

William Fragakis william at fragakis.com
Wed Jul 28 16:49:51 UTC 2010

I  just ran the same video on an Intel atom single core. I have 14
windows open in Firefox ver. 3.6, Flash ver. 10.1. I'm running F13 on
the AMD x2 server and and F12 on the client at 1280x1024. Gigabit
through two switches to the client. I'm even running Compiz on the

The youtube video runs fine. I would have difficulty saying it's an LTSP
issue unless you are running LTSP4 which is an entirely different story,

Things to check: versions of Flash and Firefox. Each edition gets better
and faster.

Just because the switches and NICs are gigabit, check that it's actually
connecting at that rate - ie not a bad cable or connection along the
line. I sometimes get a wonky connection on one of my cables and things
get as you describe - painfully slow even to use the desktop.

What color depth are you using? 32 bit is overkill and uses vastly more
resources. Make sure that the clients aren't using vesa drivers. Are you
using ssh encryption on the server client connection? It should be off
(the default, as is 16 bit). What screen resolution are you running on
the client?

Finally, that's way overkill for a core2duo to be the client. It could
serve 10-20  clients on its own. You should be running localapps or

Definitely something going on with your setup that. 


On Wed, 2010-07-28 at 12:00 -0400, k12osn-request at redhat.com wrote:
> Message: 1
> Date: Tue, 27 Jul 2010 19:08:40 -0400
> From: Joseph Bishay <joseph.bishay at gmail.com>
> To: "Support list for open source software in schools."
>         <k12osn at redhat.com>
> Subject: [K12OSN] Where is the bottleneck?
> Message-ID:
>         <AANLkTik8_Z7oWQkJ4cqeCJnUEjYc48pnB0M_sotgNf_N at mail.gmail.com>
> Content-Type: text/plain; charset=ISO-8859-1
> Hello,
> How are you doing?  I hope all is well.
> So I was recently informed by one of our staff that our LTSP
> (k12Linux) system is too slow for youtube videos.  Not being a youtube
> person (at least at work!) I had never really tried it so I gave it a
> test now.
> Setup:
> Server -> gigabit card -> gigabit switch -> gigabit client (Dell
> Inspiron 530 - Core 2 Duo processor 1 GB RAM)
> Ran the test when there was no one else logged into the network.  Gave
> the Old Spice youtube video a whirl (
> http://www.youtube.com/watch?v=owGykVbfgUE ) (ran it at 480p setting)
> and it's horrible. It's not a video as much as a fast-flickering
> slideshow.  Just to put it further I ran it at full-screen mode and it
> looked more like a powerpoint slide presentation than a video.
> I tried re-running the video several times, to see if having it in
> memory/cache made a different but it didn't.
> So I'm not sure what is the problem.  I recently purchased the gigabit
> switch specifically to help speed things up but now I'm very worried.
> What do you recommend I do in order to determine the location of the
> bottleneck?
> thank you
> Joseph 

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