1.3 JDKs Performance on Linux

Hi,
I know of three mature implementations of JDK 1.3 on Linux:
Sun's JDK 1.3, Blackdown's JDK 1.3, IBM's JDK 1.3. Which one performs best? Are there specific areas in which certain implementation is better (I can think of Swing, multithreaded apps, J2EE performance, but there might be more)?
Greg
PS. Slightly OT: the Blackdown's JDK version identifies itself as "FCS". Does anybody know what does it stand for by any chance? I couldn't find it in the release notes.

In my view , sun's jdk is standard. Because , it is coming from sun. For your information , i am just adding the link to this post .
Just check the "java performance port".
http://www.javalobby.org/features/jpr/part3.html
IBM's jdk is clear winner as compared to others. I also felt that way.just check the latest one ( Sep. 2000 , PART III )
Actually , it all depends the type of programs you going to run on that. It is you ( anybody )decide. It is really difficult to get authentic data. Also , the test ( Industry Benchmarks ) must be acceptable to you. But ,the link i have given discusses all the things in details.
I hope this is useful for you.
SHAILESH
[This message has been edited by shailesh sonavadekar (edited November 09, 2000).]

There's more to this than performance, there's also robustness to consider. I have seen several reports of problems with IBMs 1.3 VM, especially with lots of threads and particularly on multi-processor machines. Most people who had these problems have found them eliminated or much reduced by switching to Sun or Blackdown, but at some small loss in performance.
I would be wary of deploying IBMs VM as the only or main VM for a busy server site, as that is precisely where these thread problems seem most likely.

FCS usually means "Final Customer Shipment" meaning not a Beta or pre-release version.
For what its worth, I haven't done any performance tests, prefering stability instead. I use the Blackdown port when I'm working in Linux, and the Sun versions on Solaris and Windows.

Frank , can you please tell me why these problems have occured ? Whether it is inherent problem with jvm of ibm or something else ? what I mean by something else is that improper installations & improper server settings. These things are very small things , but that create a lot of problems.
The tests that are mentioned in the link that i have given seems to have standard tests. i think they are minimum possible benchmarks. People can have different view point. As far as I am concerned , I haven't heard good about blackdown's performance.
It is really difficult to tell which is good one. or one has to test by himself. can you suggest other benchmarks ?

Guys,
Thanks for your remarks. I've been using Sun's implementation just because it's from the primary source of Java technology. Blackdown people, on the other hand, are by far more experienced in JDK for Linux development, so their port might be the first choice. What do you think?
The potential worse stability of the IBM's VM is a bit of surprise to me. Their JDK 1.3 was the first non-beta release for Linux. Anyway, it's a good thing to realize.
Greg
PS. Mark, thanks for the explanation of "FCS" acronym.

I have yet to see an authoratative statement on what's wrong with IBMs JDK 1.3, but from the outside it seems as if in order to gain their speed increases they have made some optimistic assumptions about threading and interleaving of code. The observed symptoms are that some heavily used server applications (Resin, Tomcat, Orion etc.) can either lock up using 100% of the CPU, or get into a situation where none of the threads are running, so can never restart.
Some busy or heavily tested sites have reported this happening as often as every few days, which is unacceptable for a commercial server. Switching to the Sun or Blackdown ports seems to fix the great majority of these problems, but (worryingly) lockups do still sometimes seem to occur even with those.
Threading, synchronization and code interleaving is an immensely complex topic, and the Java memory Model explicitly allows some pretty wacky behaviour.

Frank , you have mentioned about tomacat. tomcat server ( Standalone ) , it is not at all withstanding heavy load. It simply crashes. There are bugs in that. I , myself have experienced the crashes. So , tomcat has to be used along with apache to have the robust perfomance. To have thread pooling , you will have to make chages to server.xml ( change from simpletcpconnection to pooltcpconnection ). I don't think it is the problem of vm.
Grzegorz , it is good choice to start with Sun's jdk. Definitely, it is offical thing. As Frank has said , the problems are there with Sun , Blackdown. It is bound to happen. Other thing which i would like to highlight is that , the performance of the server depends on hardware also ( RAM , PROCESSOR , OTHER THINGS ) . it doen't depend on software only. Regarding commercial server , i think Frank , if i have not mistake , they go for Sun - solaris.
Still , sun's jdk can be good start. Later you try others. Please let me know about your findings , Grzegorz. Frank , please tell me more abouut the problems of commercial servers that you have mentioned with ibm's jdk , if it is no problem to you.