Java on Solaris and Windows II

I really need to get to the bottom of the Benchmark in my previous post, so I have been doing a little more experimentation. As Anthony Vito pointed out, JDK1.5 optimizes the empty loops (and the simple calcs) out, so to test basic operations I need a little more work going one. I also checked the performance with the "-server" settings in JDK 1.4.2 and found almost the same optimization as JDK 1.5 (is -server the default now? can't find this). Reading the HotSpot VM FAQ verifies I should be using -server (doh! should have remembered this) for performance.

So my new test incorporates a more complex basic operation (find the 20000th prime number), a more complex FP operation (calculate PI to 7 decimal places), a large array test and CRC calculation. Although these are not exactly the operations my real application will be doing, they are some of the areas I need to test performance.

The tests are now:

1. Finding the 20000th Prime Number (I haven't tried to be clever here, its doesn't use any of the advanced math algorithms)
2. Calculating pi to 7 places (not too clever here either, but it works)
3. Writing a 50MB file
4. Reading the 50MB file using FIS.read
5. Reading the 50MB file using ByteBuffer
6. Creating 50 million item random byte array
7. Perform 64 bit CRC on the array ten times

Note, the addition of the 50M array means you need to use (at least) -Xmx128m -Xms128m in the command line. I ran this on the same Windows Laptop and Solaris Server as the previous tests in both "-client" and "-server" mode.

	Windows - Server	Windows - Client	Solaris - Server	Solaris - Client
20000th Prime	4201	12053	8722	24688
PI 7 Dec Places	2931	4901	2936	4217
Write 50MB File	6561	5882	1137	1899
FIS.Read 50MB File	1661	1852	6535	7026
Buffer.Read 50MB	480	490	1338	1425
50M Byte Array	4621	7602	12970	23306
10x50M 64b CRC	5111	8872	6969	24244

In "-server" mode the floating point test is almost identical, but basic ops (prime test) still differs by a factor of two. The memory (large array) operation is also slower on Solaris.

I'm still looking for feedback on this. Most important to me is how to speed up the basic operations (CPU intensive stuff) and improve file reading on Solaris. What I really need to test next is a C program that does the same. I want to determine if the problem is with the operating system, or the Java layer. Of course it could be with the chipset, as Anthony pointed out, but other than buy a Solaris on Intel system, I'm not sure how I can verify that (unless someone out there has one and doesn't mind running the test). I really want to use Java for this, but if C proves to perform many times better, I may be forced to reconsider.

You can download the new BenchMark java file from here.

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