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Re: [BEGINNER] How does Jigsaw react under heavy loads ?

From: Yves Lafon <ylafon@w3.org>
Date: Tue, 2 Mar 1999 16:56:57 +0100 (MET)
To: Luc Saint-Elie <stelie@pictoris-interactive.fr>
cc: Www-Jigsaw <www-jigsaw@w3.org>
Message-ID: <Pine.GSO.4.10.9903021645450.4061-100000@tarantula.inria.fr>
On Tue, 2 Mar 1999, Luc Saint-Elie wrote:

> Hello all
> 
> For some reasons I learn, develop for and use Jigsaw under Windows 98
> (mainly because I'm consultant not developper and my job is to understand
> no to create :-)
> 
> I used Apache JMeter that sends requests to and URL with Apache1.3.4/ Jserv
> 1.0b3 and JigSaw 2.0.1
> Both seems to react very differently :
> 
> Apache/Jserv tries to support the load until the PC crashes
> JigSaw reacts by working slower and slower, dosn't crash the PC, but
> doesn't seem to regain strength even after the fire ceased.
> 
> Are this behaviour only Windows 98 related or do this two servers react in
> fact differently when exposed to a heavy load ?

I don't know how if they have specific behaviour on win* but...
Apache uses several pre-forked processes, while Jigsaw use threads in one
process.
The way Jigsaw work under heavy load is the following, there is a cache of
client, with some threshold values, it has also a maximum limit. While
going to the max, the cache will start to remove some connections, which
will slow down the process, then it will refuses connections.
On the other hand, apache has several process and no global notion of A
server. It has notions of maximum childs however, but then, the limit is
for Jigsaw, the way the JDK is dividing time between threads and for
Apache the way the kernel gives resources to the process.
If your machine is on its knees, it may be because the settings of your
server are not good for your configuration. It is better to drop some
connections to avoid the big lag time (the response time/load is an
exponential curve near the limit)
I tried some load test on solaris with a good jdk
(Solaris_JDK_1.2_01_dev06_fcsV)
And when the load is back to normal, the server reacts as usual under low
load.
Regards,

      /\          - Yves Lafon - World Wide Web Consortium - 
  /\ /  \        Architecture Domain - Jigsaw Activity Leader
 /  \    \/\    
/    \   /  \   http://www.w3.org/People/Lafon - ylafon@w3.org    
Received on Tuesday, 2 March 1999 10:57:01 GMT

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