[K12OSN] Poor performance woes

Dean Jones dean.jones at oregonstate.edu
Tue Sep 20 20:34:16 UTC 2011

+1 on the 64 bit flash.  Much better performance if the problem is
flash related.

That said, i would guess that the main issue is that your 100meg
connection is maxing out and going as fast as it can.  That 12MiB/sec
is as good as you are going to get.

X is very bandwidth heavy and the network is maxed.  I would guess
that the webpage is doing something rather intense (and dumb?) with
redrawing or something display related and is just eating everything

I have similarly speced terminal clients as you describe and I can
choke them with some certain display heavy applications but going to a
gig connection makes them (more) usable.  If the clients support that
it would be an inexpensive upgrade option.

As you know Windows will perform poorly on those clients as well
regardless of the server specs.  It is dated hardware with little
video memory.

You can try nbdroot for a slight speed increase over NFS if the
problem is file i/o related.

On Tue, Sep 20, 2011 at 1:12 PM, David Hopkins <dahopkins429 at gmail.com> 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.
> 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.
> 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> 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  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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