Why is the max recursion depth I can reach non-deterministic?

by

The observed behavior is affected by the HotSpot optimizer, however it is not the only cause. When I run the following code

public static void main(String[] argv) {
    System.out.println(System.getProperty("java.version"));
    System.out.println(countDepth());
    System.out.println(countDepth());
    System.out.println(countDepth());
    System.out.println(countDepth());
    System.out.println(countDepth());
    System.out.println(countDepth());
    System.out.println(countDepth());
}
static int countDepth() {
    try { return 1+countDepth(); }
    catch(StackOverflowError err) { return 0; }
}

with JIT enabled, I get results like:

> f:\Software\jdk1.8.0_40beta02\bin\java -Xss68k -server -cp build\classes X
1.8.0_40-ea
2097
4195
4195
4195
12587
12587
12587

> f:\Software\jdk1.8.0_40beta02\bin\java -Xss68k -server -cp build\classes X
1.8.0_40-ea
2095
4193
4193
4193
12579
12579
12579

> f:\Software\jdk1.8.0_40beta02\bin\java -Xss68k -server -cp build\classes X
1.8.0_40-ea
2087
4177
4177
12529
12529
12529
12529

Here, the effect of the JIT is clearly visible, obviously the optimized code needs less stack space, and it’s shown that tiered compilation is enabled (indeed, using -XX:-TieredCompilation shows a single jump if the program runs long enough).

In contrast, with disabled JIT I get the following results:

> f:\Software\jdk1.8.0_40beta02\bin\java -Xss68k -server -Xint -cp build\classes X
1.8.0_40-ea
2104
2104
2104
2104
2104
2104
2104

> f:\Software\jdk1.8.0_40beta02\bin\java -Xss68k -server -Xint -cp build\classes X
1.8.0_40-ea
2076
2076
2076
2076
2076
2076
2076

> f:\Software\jdk1.8.0_40beta02\bin\java -Xss68k -server -Xint -cp build\classes X
1.8.0_40-ea
2105
2105
2105
2105
2105
2105
2105

The values still vary, but not within the single runtime thread and with a lesser magnitude.

So, there is a (rather small) difference that becomes much larger if the optimizer can reduce the stack space required per method invocation, e.g. due to inlining.

What can cause such a difference? I don’t know how this JVM does it but one scenario could be that the way a stack limit is enforced requires a certain alignment of the stack end address (e.g. matching memory page sizes) while the memory allocation returns memory with a start address that has a weaker alignment guaranty. Combine such a scenario with ASLR and there might be always a difference, within the size of the alignment requirement.

More Related Contents:

  1. Why does the count of calls of a recursive method causing a StackOverflowError vary between program runs? [duplicate]
  2. Recursive ConcurrentHashMap.computeIfAbsent() call never terminates. Bug or “feature”?
  3. Implement recursive lambda function using Java 8
  4. java.lang.StackOverflowError due to recursion
  5. Operations on Strings
  6. How will Java lambda functions be compiled?
  7. Any difference between java.time.Clock.systemDefaultZone().getZone() vs java.util.TimeZone.getDefault().toZoneId()?
  8. How to fix ambiguous type on method reference (toString of an Integer)?
  9. Adding up BigDecimals using Streams
  10. Printing debug info on errors with java 8 lambda expressions
  11. How many threads are spawned in parallelStream in Java 8?
  12. Mocking time in Java 8’s java.time API
  13. Minimum Spring version compatible with Java 11
  14. Convert between LocalDate and sql.Date [duplicate]
  15. RejectedExecutionException inside single executor service
  16. How to use a Java8 lambda to sort a stream in reverse order?
  17. Why parallel stream get collected sequentially in Java 8
  18. How to extract epoch from LocalDate and LocalDateTime?
  19. Can program developed with Java 8 be run on Java 7?
  20. Variable is already defined in method lambda
  21. Java 8 Lambda Expression Within REST Service not working
  22. Can a java lambda have more than 1 parameter?
  23. How to set IntelliJ IDEA Project SDK
  24. Get original pattern String given a JDK 8 DateTimeFormatter?
  25. What’s the purpose of partitioningBy
  26. Using method reference instead of multi argument lambda
  27. Default garbage collector for Java 8
  28. Purpose of third argument to ‘reduce’ function in Java 8 functional programming
  29. Does collect operation on Stream close the stream and underlying resources?
  30. How to get multiple values from an object using a single stream operation?

Leave a Comment