RE: Servlet Load Times under WAS on an iSeries!

Sal,

It sounds like you configuration is identical to mine but I do not see the
problems you are describing.  I am at V5R1 with the latest fixes.  I also
am running Tomcat on my iSeries. The advantages of Tomcat are that
it has the latest support for JSP and Servlets. It also uses less system
resources and is simple to deploy. Disadvantages are no EJB support
and it probably doesn't scale as well. I have not tried Tomcat 4.0 on the
iSeries, but it adds more neat stuff like context sensitive changes and
filtering.

To make Tomcat run fast you do have to precompile everything.  I have
found that very large configurations may cause class loading problems.
That would be somewhere around 15M of Jars in Tomcat's lib directory.
The Jasper compiler that comes with Tomcat is slow on the iSeries but it
only runs the first time a new JSP changes. Also, some Jar files do not
work as Jars and have to be unpacked to run???. I do not have a support
line contract to pursue these and have worked around them at this point. I
see sub-second response on fairly complex JSP pages.

David Morris

>>> joepluta@PlutaBrothers.com 09/12/01 10:19AM >>>
I talked to Sal about this offline, just to make sure I understood, and we
came to the conclusion that it's probably his machine.  Sal's running a
270-2248, and we've both heard whispers that it doesn't have an L2 cache,
unlike my 270-2250.  Also the 2248 has a CPW of 150, and the 2250 has a CPW
of 370, and my machine has twice the memory of Sal's.

All these together make my machine run maybe 10 times faster on an initial
servlet load.  There's little or nothing that can be done about that, short
of preloading the servlets.

I think we'd all appreciate hearing from anybody else about this, especially
the L2 cache issue.

Joe


> -----Original Message-----
> From: Sal Stangarone Jr.
> Sent: Wednesday, September 12, 2001 10:02 AM
> Subject: Servlet Load Times under WAS on an iSeries!
>
> I have some simple servlets that I've deployed on our iSeries
> under both WAS
> 2.02 and 3.5.2 and in both instances the initial load times are
> unacceptable
> (15 seconds or more).  Once loaded they perform well (under 2 seconds).  I
> know I can have the Servlets loaded as part of the WAS startup but I don't
> understand why these servlets take so long to load on our iSeries.  I've
> deployed the same servlets to a standalone PC utilizing Tomcat as
> the server
> and I see minimal (under 5 seconds) startup time needed there even though
> its a small PII 233 PC.
>
> I have tried optimizing my class file to opt 40 and while that has some
> effect it's minimal.  Has anyone else experienced this?  Is this WAS or my
> iSeries any ideas?