Classic or HotSpot JVM under HP-UX 11i - problems

[Andre Lafrance]

Hi all,

We have been running our Java application (we are an
ASP) on Sun E420R Servers under Solaris 7 using the
Sun JDK 1.2.2_07 (the "Exact" or Classic VM).

Recently, we have moved to the HP 9000 platform and
intend to use A500 servers with the HP 1.2.2_09 JVM.

Since our application has problem running under Hotspot
both on Sun or HP, we want to use the Classic VM on
HP, as we do on Sun. But performance is terrible.
For example, on our load-tests:

Sun E420R (4 x USparc-II 450MHz)
Solaris 7
JDK 1.2.2_07, Exact VM
Average CPU Usage: approx. 15%
Average Servlet call run time: approx 450ms.

HP A500 (2 x PA-8500 440MHz)
HP-UX 11i
JDK 1.2.2_09, Classic VM
Average CPU Usage: approx. 65%
Average Servlet call run time: approx 650ms.

We also tried HotSpot on HP but it crashed
3 times, a different way each time (we may have
threading problems with HotSpot).

HP A500 (2 x PA-8500 440MHz)
HP-UX 11i
JDK 1.2.2_09, HotSpot VM
Average CPU Usage: approx. 20%
Average Servlet call run time: approx 600ms.

It's obviously better, but it crashes...

I understand, of course, that the Sun box is a 4 CPU
system, but the HP uses more powerful CPUs
(according to SPEC anyways) so this difference is
somewhat offset.

We patched the HP-UX box with the latest HP-UX
patches for Java on 11i and tuned the kernel to
the satisfaction of HPJconfig. According to my own
analysis, our kernel parameters look good.

I noticed something that freaked me out with the HP
JDK 1.2.2_09 Classic - it uses by default the java binaries
in the PA_RISC directory instead of the PA_RISC2.0
directory (HotSpot uses these).
Thus:
Classic:
/opt/java1.2/bin/../bin/PA_RISC/native_threads/java
HotSpot:
/opt/java1.2/bin/../bin/PA_RISC2.0/native_threads/java

Does this mean that the Classic VM is compiled for a
PA-RISC1.1 system? Does this explain the terrible
performance? Am we stuck trying to debug our
application on HotSpot on HP when before, with the
Sun JVM, we had stable performance with the
Classic (or "Exact") VM?

Thanks for any help!

Andre