[K12OSN] Poor performance woes

Jomegat jomegat at jomegat.com
Tue Sep 20 20:23:02 UTC 2011

On 09/20/2011 04:12 PM, David Hopkins wrote:
> So, runs fine at server console, but lags severely at the thin client
> with the same account.  Are you certain that the clients are running at
> 100Mb full duplex?  If you've enabled a shell at the client can you
> check to see what ifconfig reports at the client?  I would check
> memory/performance at the client with top (in a shell, add
> SCREEN_02=shell in lts.conf, ctl-alt-f2 to access it at the client)
> while the page is being displayed from the GUI login session just to
> convince myself it isn't a load issue at the client.

I will double check, but since I was seeing 12MiB/sec - which is pretty 
close to 100 Mbits/sec, I'm thinking they are running at 100.  Also, the 
LEDs on the switch say 100, and not 10.

> Also, Adobe has a 64bit Flash for linux (v11) available as beta. I've
> been running that for the last couple of weeks (since it was released
> IOW) on my systems (Ubuntu 10.04 with LTSP packages added).
> http://labs.adobe.com/downloads/flashplayer11.html It definitely runs
> better than the 32bit flash with nswrapper.  Installation was just a
> matter of  uninstalling the 32bit flash and copying the 64bit version to
> the correct plugins directory.

Yes, I'm using the 64-bit Flash, and not the nswrapper version. 
Further, I can't find any flash content in the page he's loading, just a 
truckload of javascript.

> Those are the things that I'd check first.


> Sincerely,
> Dave Hopkins
> Newark Charter School
> On Tue, Sep 20, 2011 at 3:18 PM, Jomegat <jomegat at jomegat.com
> <mailto:jomegat at jomegat.com>> wrote:
>     I have a K12Linux setup based on EL6-64.  The TC's are ancient
>     i686's with 256M RAM and 10/100 nics.  The TS has a gigE NIC, and
>     between the TS & TCs is a managed switch with 2 gigE ports and 24
>     10/100 ports.  The TS is connected via one of the gigE's.
>     We have a student who is having real performance problems when he
>     loads a page.  I went in today to be there while he was experiencing
>     woe, and ran the system monitor applet.
>     When he loads the web page - with no flash in it that I can find -
>     the network maxes out at 12MiB/sec, and it takes an eternity for the
>     page to load.  He reports that sometimes this particular page will
>     cause the TC to crash (black screen with text followed by login
>     screen), but he was not able to reproduce that while I was there.  I
>     suspect there is some user error involved in the crash scenario, but
>     it will be difficult to prove.
>     I had tried running firefox as a local app last month, but the
>     school needs flash, and it requires 512M.  Performance on these TC's
>     was substantially worse when running FF as a local app, so I backed
>     off of that.
>     The page he was trying to load is password protected, but I had him
>     ctrl-U while he had it open, and save the source to a file which I
>     can share if need be.  It is filled with javascript, but I'm not
>     sure that's the culprit (though it seems the most likely suspect).
>       I found no .flv, FLV, .swf, or .SWF in the file anywhere.
>     As an experiment, I connected a monitor, keybd, and mouse directly
>     to the server and had him login there.  The page loads just fine
>     that way.  That might be a possible solution, but for some reason,
>     the display is incredibly blurry.  If I make that permanent, I'd
>     have to run some cable through the wall (they're pinched in the door
>     right now, and barely reach).
>     Before they called me in to look at this, he had been bringing his
>     mom's laptop to school so he could do his work (it's an online
>     course).  If it crashes while he is taking a quiz, he loses a test
>     attempt or gets a bad grade, so this has to be reliable.
>     His mom is on the school board, and she is pushing the school to
>     abandon LTSP in favor of a Windows solution.  They think that if
>     they install some flavor of windows on the TC's they will get better
>     performance, but I believe they won't, as flash will need 512M no
>     matter the OS.  I think they will need all new PC's if they go that
>     route.
>     I am on the cusp of losing my network to Windows, at which point I
>     will resign my post as unpaid volunteer sysadmin, so if I sound a
>     little desperate, now you know why.
>     Any help here would be greatly appreciated.
>     --
>     Jim Thomas            Principal Applications Engineer  Bittware, Inc
>     jthomas at bittware.com <mailto:jthomas at bittware.com>
>     http://www.bittware.com (603) 226-0404 x536
>     <tel:%28603%29%20226-0404%20x536>
>     The problem with the future is that it keeps turning into the
>     present - Hobbes
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Jim Thomas            Principal Applications Engineer  Bittware, Inc
jthomas at bittware.com  http://www.bittware.com    (603) 226-0404 x536
The problem with the future is that it keeps turning into the present - 

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