Re: Java and CPU

Brad,

Resource comparisons between java and it's runtime environment, and rpg are
hard to come by.  For that, I appreciate your post.  But even the little you
gave us is still mostly an apples to oranges comparison.  If anyone has more
meaningful data, I'd appreciate hearing about it.

Websphere is statically linked to the HTTP Server.  It's CPU use is
reflected in the HTTP server jobs.  CGIs are dynamic calls to external
programs.  Their CPU use is separate.  The call to the CGI takes some work.
So does the handling of the CGI I/O.  That minimal use is reflected in the
Server's BCI jobs.  But the CGIs themselves, are separate jobs altogether.

I wrote a plug-in for the HTTP Server which does some message handling.
Like Websphere, it's statically linked.  When I stress test my plug-in, I
see lots of threads in the BCH job active, but no extra BCI jobs get
started.  The ones that were there to begin with, just sit in a TIMW status,
with zero CPU use.

BTW, were both machines identical?

Nathan.

----------- original ------------------
Date: Thu, 1 Mar 2001 14:34:49 -0600
From: "Stone, Brad V (TC)" <bvstone@taylorcorp.com>
Subject: Java and CPU

This I found interesting.

We have an AS/400 that is a web server only.  We're running CGI to do
customer service online for multiple customer/catalogs.  Right now it's
about 30 sites (all using the same 3 or 4 programs, webfacing controled by
config files, SSIs, etc..).

Some CPU stats for the normal HTTP Server: (jobs entered system 2/14/2001)
Subsystem/Job  Type  Pool  Pty      CPU
CSO            BCH     2   25    1516.4
CSO            BCI     2   25        .1
CSO            BCI     2   25        .3
CSO            BCI     2   25      69.0
CSO            BCI     2   25      26.1
CSO            BCI     2   25     727.4

Now, I have also have websphere running.  I've been trying to duplicate this
CGI system using servlets and and making progress (no wonder I'm asking so
many questions!).

Anyhow Here's the CPU stats for the default WAS server that is processing
the servlets: (entered system 2/19/2001)

Subsystem/Job  Type  Pool  Pty      CPU
DEFAULT_SE     BCI     2   25+   2847.7
QEJBADMIN      BCI     2   25+   6203.9
QEJBMNTR       ASJ     2   25        .1

The HTTP server has received about 7000 hits since it started on 2/14/2001.
This server serves up those 30 sites and is available 24/7.

The WAS server hasn't even broken a couple hundred hits since it's only me
testing when I have time (started on 2/19/2001).  It's not available to the
interent and I am the only developer on the box.

The Java version of the application isn't querying customer service data
yet, I'm simply building the web pages.  The CGI programs run dynamic SQLs
to select and display data depending on customer signon information.

The numbers compared to just the default WAS server may be close, but
remember, it's doing about 1/100th of the work right now.

Any thoughts, ideas, or otherwise?  I'm really wondering why so much more
CPU is used.  If I were to take my app and java-ize it, it looks like it
would bury the current machine we are using.

Last question, does WAS start more instances when it needs to them to handle
more requests like the HTTP server does?  What about the new Apache server,
does it start more jobs to handle more requests?

Thanks!

Brad


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