Java stack vs. real stack

Pavel Roskin pavel_roskin at
Mon May 17 06:44:43 PDT 1999


I have investigated why StackOverflowError is thrown in AWT programs when
Kaffe uses the interpreting engine.

Hare are my results.

1) -ss switch doesn't affect stack size of the main thread in Kaffe. It is
always 1M (RedHat-6.0, i686, Linux-2.2.9). However, in JDK 1.1.7v2 -ss
affects all threads.

2) In the simplest case when functions are called without arguments (see
test/regression/ JDK consumes 44 bytes per java call,
Kaffe/JIT consumes 88 bytes, and Kaffe/Interpreter wastes 516 bytes!!!

3) Alone "vmException mjbuf;" at kaffe/kaffevm/intrp/machine.c:77 consumes
172 bytes per java call.

AWT programs in Kaffe/Interpreter with 32k (default!) stack throw
StackOverflowError when Java stack contains approximately 80 calls.
Unfortunately, AWT runs in a separate thread, so this happens almost for
all programs.

Ideas? Suggestions?

Pavel Roskin

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