This is like saying "here's my first program written for CICS in COBOL. How long does it take and how many resources are consumed to start CICS and run it?" (and BTW, I don't know much about CICS and I haven't bothered to tune it)
Granted, there is a bit of work starting up a Java JVM on z/OS, so its not ideal for really short jobs. Re: 6 seconds - not sure what elapsed time means in your environment, but I can start Apache Tomcat on z/OS (a pretty big Java app) in 3 seconds. If your goal was to tune startup of the JVM for short jobs, you would probably use shared classes and the quickstart JIT option. With that, you could probably start in around a half a second CPU time. Re: 96M - z/OS Java's default maximum heap size is 64 MB and it will allocate all of it when it starts up. Add in the non-heap storage and native code size and 96MB sounds about right. You probably didn't need 64MB of heap to run your program. Although the "fixed" costs of starting a Java JVM are a little steep, the incremental costs of running code in a medium to long running job or container can be pretty competitive. You still have to deal with the common issue that most Java programmers don't know how to write efficient code that scales up.... Kirk Wolf Dovetailed Technologies http://dovetail.com On Thu, Nov 26, 2009 at 6:48 AM, Roger Bowler <[email protected]> wrote: > On Thu, 19 Nov 2009 17:25:19 -0600, Kirk Wolf <[email protected]> wrote: > > > I don't know if it's undeserved or not, but Java on z does have a reputation > for being a resource hog. I just ran the hello world sample program on a z10 > : it took 6 seconds elapsed time and required a region size of 96M (yes, > that's 96 MEGABYTES!). Just to print "hello world". And that doesn't include > the compile. > > Scale this up and it's not surprising that IBM are reporting record sales of > z hardware! > > Roger Bowler > Hercules "the people's mainframe" > > PS: Here's the program: > > public class test1 { > public static void main (String args[]) { > System.out.println("test1: Java on zSeries"); > } > } > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to [email protected] with the message: GET IBM-MAIN INFO > Search the archives at http://bama.ua.edu/archives/ibm-main.html > ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
