Benchmark / Performance Test in mauve

[Robert Schuster]

Hi,
this topic may belong to mauve but I am not sure whether all the VM implementors
are on that list.

Recently there was a discussion[0] on the sdljava list about the efficieny of
direct NIO buffers and Java arrays. It took place because OpenGL functions like
glVertex3fv(float[]) in C where mapped to Java methods like this
glVertex3f(FloatBuffer). If you don't know OpenGL: the functions expect that the
array/buffer contains only 3 values.

A user of the sdljava library (which is currently tied together with gljava)
found out that it is better to use Java arrays as arguments here. He expected
his application to do frequent allocations of the buffer/arrays and this would
kill performance in case of the direct NIO buffers.

To underly this he wrote a small benchmark (which we are allowed to license
under GNU GPL[1])

I remember that once upon a time Michael said we should test for performance
regressions in mauve and I think the attached benchmark could be used for that.

Ideas, thoughts anything?

Anyway, if have not read the sdljava discussion thread. Here are the benchmark
results for two of our free VMs in comparison with JDK1.5.0 on my machine
(Athlon XP 2200+ w/ 512 MB Ram):

address@hidden ~/tmp/test/bench/buffer-vs-arrays $ LD_LIBRARY_PATH=. gij 
Benchmark
running Test Benchmark$TestArrayReallocate for 1000000 times
result: 2705
running Test Benchmark$TestArrayAllocateOnce for 1000000 times
result: 2242
running Test Benchmark$TestByteBufferReallocate for 1000000 times
result: 4329
running Test Benchmark$TestByteBufferAllocateOnce for 1000000 times
result: 1047

(This is GCJ 4.0 somewhat.)

address@hidden ~/tmp/test/bench/buffer-vs-arrays $ LD_LIBRARY_PATH=. jamvm 
Benchmark
running Test Benchmark$TestArrayReallocate for 1000000 times
result: 1825
running Test Benchmark$TestArrayAllocateOnce for 1000000 times
result: 1443
running Test Benchmark$TestByteBufferReallocate for 1000000 times
result: 7916
running Test Benchmark$TestByteBufferAllocateOnce for 1000000 times
result: 278
address@hidden ~/tmp/test/bench/buffer-vs-arrays $

(Both are interpreted only. JamVM has a handcrafted JNI implementation that
really outperforms the JDK)

As a comparison my JDK 1.5.0 results:
LD_LIBRARY_PATH=. /opt/sun-jdk-1.5.0/bin/java Benchmark
running Test Benchmark$TestArrayReallocate for 1000000 times
result: 484
running Test Benchmark$TestArrayAllocateOnce for 1000000 times
result: 386
running Test Benchmark$TestByteBufferReallocate for 1000000 times
result: 15891
running Test Benchmark$TestByteBufferAllocateOnce for 1000000 times
result: 287

Well done hackers!

cu
Robert

[0] - 
http://sourceforge.net/mailarchive/forum.php?thread_id=8148756&forum_id=43388

[1] - http://sourceforge.net/mailarchive/message.php?msg_id=12939689

nio-benchmark.tar.gz
Description: GNU Zip compressed data