hotspot « performance « Java Testing Q&A

1. First time a Java loop is run SLOW, why? [Sun HotSpot 1.5, sparc]    stackoverflow.com

In benchmarking some Java code on a Solaris SPARC box, I noticed that the first time I call the benchmarked function it runs EXTREMELY slowly (10x difference):

• First ...

2. How can I code Java to allow SSE use and bounds-check elimination (or other advanced optimizations)?    stackoverflow.com

The Situation:

3. Java Condition Operators Speed vs Versions of Hotspot VM    stackoverflow.com

Please consider the following java source:

package com.stackoverflow;

 public class CondSpeed {
 private static final long COUNT = 1000000000;
 private static final long OUTER_COUNT = 15;

 private static long notEqOperator = 0L;
 ...

4. Java/JVM (HotSpot): Is there a way to save JIT performance gains at compile time?    stackoverflow.com

When I measure the throughput of my Java application, I see a 50% performance increase over time:

• For the first 100K messages, I get ~3,000 messages per second
• For the second 100K messages, ...

5. Why's Java in this case faster (and slower) than C?    stackoverflow.com

Some fellow just started learning C by reading K&R and came up with its fahrenheit-to-celcius conversion loop printed down on the first pages:

#include <stdio.h>

main ()       ...

6. Where can I find information about the inner workings of Sun's JVM?    stackoverflow.com

As a developer, I want to know what the cost is of invoking a virtual method vs. interface method. Now, I know why invokeinterface can be slower than invokevirtual, but ...