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Re: [K12OSN] Poor performance woes

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.


Dave Hopkins
Newark Charter School

On Tue, Sep 20, 2011 at 3:18 PM, Jomegat <jomegat jomegat com
<mailto:jomegat 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

    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 bittware com <mailto:jthomas bittware com>
    http://www.bittware.com (603) 226-0404 x536
    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 bittware com  http://www.bittware.com    (603) 226-0404 x536
The problem with the future is that it keeps turning into the present - Hobbes

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