Performance of Java on FBSD vs. others...

[Nikos Ntarmos]

Hi all.

I've spent the last week or so running the exact same Java code on the
exact same hardware, under different OSs. The code i'm running is
heavily cpu-bound (no i/o other than light logging), uses a lot of
memory (~1G), and does not rely on threading libraries (i.e. the program
creates two threads when it starts and that's all about it).

I'm running a small and a large version of the program (wrt memory
requirements and run-time). The average execution time for the small
version goes from ~200'' under win32, to ~220'' under linux, and to
~800'' under freebsd. For the large version, the numbers are ~1600''
for win32, ~1800'' for linux, and ~4700'' for freebsd.

This is all on a 1.7GHz Pentium-M laptop with 1G RAM (dmesg at
http://ntarmos.dyndns.org/Computers/dmesgs/ace.dmesg), running -current
as of Sep 29. The JDKs tested are diablo-jdk15 (1.5.0.07.01) and
sun-jdk15 (1.5.0p6) for FreeBSD, and sun-jdk15 (1.5.0_07) for linux and
win32.

Does anybody else see such a performance drop across OSs? Is there some
specific (known) reason why freebsd lags behind the other two OSs by
this 3x-4x factor? Any pointers as to some (sysctl or other) knob I've
missed?

Thanks in advance.

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