Wow - I didn't expect such a performance increase: our server app that already had a 80% performance part of database access increased by almost 30% just by switching the 1.5 JRE (with server HotSpot) with the new 1.6 JRE! This looks good! :-)

 

 

Wait - so you're saying that the 20% that are not database access now only take -10%?

 

 

Well, the app calculates 30% faster than with 1.5 (server HotSpot). The "80%" database part is just an estimation as I enclosed the methods that access the database with timestamps that make up to 80% of the whole performance. So, these 80% include the (JDBC) code to read/write from/to database, JDBC driver code and the final database time.

I checked today again, and the 30% increase stayed. :-) However another app just increase by 10% (which is already very good) because this other app had a lot more access to external ressources (JDBC, file system, SOAP).

I guess, for specific apps, the performance increase can be even higher depending on the componentes/ressources involved.

 

 

Martin,

Is there any chance you could share your benchmark with us? We're always interested in analyzing the performance characteristics of production code. And if we know what's going on within your app we're better equiped to either improve upon (or at least retain) the performance benefits you're seeing.

Regards
Dave (dice at east dot sun dot com)

 

 

I didn't test with Benchmarks but with real world production applications. And now I even noticed a 100% speed increase: I downloaded the 64 Bit Linux version for my 64 Bit Ubuntu 6.10. And my Fractal programm runs (compared to 1.5.0_08 for the same Linux system) ub to 100% faster!!! It starts with the basic Mandelbrot set with an 20% increase and ends up with a full 100% increase at my test location

-0.5622026215230372, 0.6428171490727752, 2.220446049250313E-15 with 300 Iterations!

Yes, it takes 10 instead of 20 seconds just by replacing JDK 1.5 width JDK 1.6! That's so awesome!!! :-)

 

 

Hello, I made other experience.
I do mathematics with java. It is running under Windows.
My main routine is just a simple for loop with a subtraction.
JDK 1.5 (or JDK 1.4) with -server and IBM Java 5 (JIT) have the same performance.
jdk 1.6 with -server needs 50% extra time.
jdk 1.6 (and jdk 1.5) without -server need 70 extra time.

The -server hotspot optimization was much better in jdk 1.4 or 1.5.
Why?

 

 

Well, did you try the JRE instead of the JDK? The SDK binaries are with debugging code. Just copy the server HotSpot directory to the JRE installation and try again.

Well, you might have made other experience, but you can't say that "The -server hotspot optimization was much better in jdk 1.4 or 1.5." because it is not true because all our applications (and also 3rd party Java apps like Eclipse) run considerably faster with Java 1.6. And HotSpot server is still much better than client for number crunching apps.

 

 

I copied the Java\jdk1.6.0\jre\bin\server dir to Java\jre1.6.0\bin,
changed the JRE in the windows preferences, in the project and in the Running environment. No changes.

 

 

Interesting Phaenomen the application is producing different outputs under different jdk's so the performance analysis is misleading.

But different output under JDK 1.6, what is this???

Forget the statement concerning the speed, i have to check my code.

 

 

Could you please document that assertion.


Except of course that the user has a specific benchmark that specifically demonstrates that.

 

 

I checked the sources. They changed the behavior of Random, so different inputs were generated.

But JDK 1.5_8 -server still performs slightly better at my application then JDK 1.6 -server (about 5%).
JDK 1.6 performs like JDK 1.4_12.

Have you tried IBMs Java50 jre it is at most as fast as JDK 1.5_08.

My code runs faster in JDK 1.4 style.

 

 

SDK and JRE 1.6 have the same performance in my tests.

 

 

Here were my results based on my Factoring Algorithm:
The execution times relative to JDK 1.5.0 _08 -server which was the fastest

JDK 1.4 _12 1,43
JDK 1.4_12 -server 1,05

JDK 1.5.0 _08 1,48
JDK 1.5.0 _08 -server 1,00

JDK 1.6.0 1,16
JDK 1.6.0 -server 1,05

IBM JAVA 5 -Xnojit ~ 7
IBM JAVA 5 1,00

 

 

I have read that somewhere but can't find the resource now. You can easily check the binaries. Also check the sizes:

JRE/lib/rt.jar = 40 MB
JDK/jre/lib/rt.jar = 44 MB

And you can write test code that throws an exception: with the JRE you will get a stack trace without line numbers ("Unknown source") and with the JDK you will get line numbers.

 

 

You do realize that the JDK comes with the JRE right?

So you don't copy files - you just use the correct directory.