Hi,
I ported a standalone java application to z/OS. I tried to compare the peformance of my application between the Sun JDK 5.0 and the IBM JDK 1.4.2. The Sun 5.0 was much faster (15 times).
In a next step I thought that upgrading to IBM JDK 5.0 would lower this difference. However the IBM JDK 5.0 was even slower than the 1.4.2.
Does anybody has similar experiences? Are there any tools that I can use to tune the application directly on the mainframe?
Regards
Performance testing
YMMV, but the raw speed of the the JVM under z/OS tends not to compare well with an Intel chip. (The same can be said for "C" applications)....
Also remember that most z/OS systems are shared by hundreds of concurrent applications and users, so you may not be making an apples-to-apples comparision.
That said, many Java applications, especially I/O intensive stuff, run acceptably well on z/OS.
Also remember that most z/OS systems are shared by hundreds of concurrent applications and users, so you may not be making an apples-to-apples comparision.
That said, many Java applications, especially I/O intensive stuff, run acceptably well on z/OS.
Performance surprise...
I've been involved in setting up some standalone processes utilizing Java on z/OS. Basically, we are using Java on z/OS to parse inbound(into Legacy system) XML using a SAX parser and JAXB2.0 to marshal and write outbound(out to J2EE) XML.
During our testing, we've also been surprised by the performance. My background is primarily in mainframe programming... Assembler,COBOL,CICS. My expectation was that our process would blaze once we ported our code from PC to the z/OS.
On z/Os, our process takes twice as long CPU time as it does wall-clock time on my PC. We've submitted a ticket to our systems folks but none of them are familiar with Java on z/OS so I don't know how much traction we'll get.
We originally started out using BPXBATSL but more recently opted for the JZOS Batch Launcher. The launcher is really well done.
Any thought or suggestions about performance enhancement would be greatly appreciated.
Thanks,
Randy
During our testing, we've also been surprised by the performance. My background is primarily in mainframe programming... Assembler,COBOL,CICS. My expectation was that our process would blaze once we ported our code from PC to the z/OS.
On z/Os, our process takes twice as long CPU time as it does wall-clock time on my PC. We've submitted a ticket to our systems folks but none of them are familiar with Java on z/OS so I don't know how much traction we'll get.
We originally started out using BPXBATSL but more recently opted for the JZOS Batch Launcher. The launcher is really well done.
Any thought or suggestions about performance enhancement would be greatly appreciated.
Thanks,
Randy
I have three suggestions:
1) Rule out that you have a LE config/tuning problem. Contact IBM support and get the latest version of "jdkiv" for your version of Java. You may also want to run an LE options and storage report and verify that there is not a problem with your LE settings that is causing poor JVM performance. The Java diagnostics guide and the IBM support center may be able to help you if you don't have experience with LE.
2) Use a performance monitoring tool to find out which parts of your application are causing the most problems. If you are using Java 5, you might try "jiprof" (http://jiprof.sourceforge.net/).
3) Other that the IBM support centers, the best places to get support for z/OS SDK performance problems are probably the following two forums. I would strongly suggest that you repost your question there as well.
http://www.ibm.com/developerworks/forum ... 367&cat=10
http://www.lsoft.com/scripts/wl.exe?SL1 ... MARIST.EDU
Good luck. As mentioned in a previous post, zSeries hardware often doesn't compare well to Intel with either C or Java for compute-bound applications, but many Java applications can be made to run well on z/OS. Hopefully some tuning will uncover a problem that helps you get this running better.
1) Rule out that you have a LE config/tuning problem. Contact IBM support and get the latest version of "jdkiv" for your version of Java. You may also want to run an LE options and storage report and verify that there is not a problem with your LE settings that is causing poor JVM performance. The Java diagnostics guide and the IBM support center may be able to help you if you don't have experience with LE.
2) Use a performance monitoring tool to find out which parts of your application are causing the most problems. If you are using Java 5, you might try "jiprof" (http://jiprof.sourceforge.net/).
3) Other that the IBM support centers, the best places to get support for z/OS SDK performance problems are probably the following two forums. I would strongly suggest that you repost your question there as well.
http://www.ibm.com/developerworks/forum ... 367&cat=10
http://www.lsoft.com/scripts/wl.exe?SL1 ... MARIST.EDU
Good luck. As mentioned in a previous post, zSeries hardware often doesn't compare well to Intel with either C or Java for compute-bound applications, but many Java applications can be made to run well on z/OS. Hopefully some tuning will uncover a problem that helps you get this running better.