Re: [Help-smalltalk] the test test - an experience report

[Stefan Schmiedl]

On Fri, 17 Jul 2009 13:12:45 +0200
Paolo Bonzini <address@hidden> wrote:

> Thanks for the experience!

I left out the horrific part where the usual last minute fix from the
night before broke half of the system ...

> 
> >  From the users' point of view, it was a nice change
> > of things, and they quite liked it, once we got over
> > the initial hurdle (below).
> 
> What were they using before?

usual school equipment: paper and pencils :-)

> > I have saved the images of every run
> >    gst-remote --eval="ObjectMemory snapshot"
> > and will try to find out what has caused this growth.
> 
> What is the actual size of the images?

address@hidden testdrive $ ls -l ../ot.im *.im
-rw-r--r-- 1 stefan stefan  6234160 16. Jul 17:14 ../ot.im   <- "clean image"
-r--r--r-- 1 stefan stefan 76702080 16. Jul 09:30 ot6a.im    <- "used image"
-r--r--r-- 1 stefan stefan 92434208 16. Jul 10:35 ot6b.im    <- "special case"
-r--r--r-- 1 stefan stefan 74360512 16. Jul 11:24 ot6c.im    <- "used image"
-r--r--r-- 1 stefan stefan 79733448 16. Jul 11:59 ot6d.im    <- "used image"
-r--r--r-- 1 stefan stefan 79306448 16. Jul 12:33 ot6e.im    <- "used image"

The "special case" was a group of students who were sitting there somewhat
longer, probably clicking around some more. 

> > The students of class 6a logged into their Windows domain accounts,
> > started Firefox and entered the URL for the test (stage 1 above).
> > Then they entered their names into the registration page (stage 2)
> > and clicked on the button to access the test. Shortly after server
> > CPU load went to 100% with the following error message being
> > repeated as fast as the remote terminal could cope with:
> >
> >    "Socket accept error: Error while trying to accept a socket
> > connection"
> 
> Do you have the backtrace?

There's not much in there. I only have two logs, one contains:

Loading package Sockets
Loading package Sport
Loading package Iconv
Loading package Iliad-Core
Loading package Iliad-More-UI
Loading package Magritte
Loading package Iliad-More-Widgets
Loading package Iliad-More-Magritte
Loading package Swazoo
Loading package Iliad-More-Examples
Loading package Iliad-More
Loading package Iliad-Swazoo
Loading package Iliad
Loading package OnlineTester
gst-remote server started.
Socket accept error: Error while trying to accept a socket connection.
... repeated 34461 times until pkill gst-remote ...
/usr/local/share/smalltalk/kernel/../scripts/Remote.st:281: Terminated
(ip 12)HomedAssociation(Association)>>#=
(ip 38)Set>>#findIndex:
(ip 6)Set(HashedCollection)>>#findIndexOrNil:
(ip 4)Set(HashedCollection)>>#remove:ifAbsent:
(ip 8)Set(Collection)>>#mourn:
(ip 6)HomedAssociation>>#mourn
(ip 4)[] in ProcessorScheduler>>#initialize
(ip 24)Array(SequenceableCollection)>>#do:
(ip 6)[] in ProcessorScheduler>>#initialize
(ip 4)[] in BlockClosure>>#newProcessWith:
(ip 52)[] in Process>>#onBlock:at:suspend:
(ip 10)<unwind> BlockClosure>>#on:do:
(ip 14)[] in Process>>#onBlock:at:suspend:
(ip 4)<unwind> BlockClosure>>#ensure:
(ip 10)[] in Process>>#onBlock:at:suspend:
(ip 42)[] in BlockClosure>>#asContext:
(ip 12)BlockContext class>>#fromClosure:parent:

and the other ends with the "Remote.st:281: Terminated" line after 40417
"Socket accept error" lines. In that case, I'm fairly sure that the time between
the first error and the pkill was below 1 min.

> > I'll try to build a test bed to reproduce the disaster in a
> > controlled setting, but it will be a few days before I can really
> > get to this.
> >
> > Any ideas?
> 
> You could use Ruby's Mechanize for that. 
> http://mechanize.rubyforge.org/mechanize/ -- just to show we're not 
> zealots! :-)

huh ... ruby, gst, what's the difference?

ducking and covering,
s.