[HADOOP-18429] MutableGaugeFloat#incr(float) get stuck in an infinite loop

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.4.0
• Fix Version/s: 3.4.0
• Component/s: metrics
• Labels: pull-request-available
• Target Version/s: 3.4.0
• Hadoop Flags: Reviewed
• Assignee: Ashutosh Gupta
• Reporter: asdfgh19
• Created: 29/Aug/22 11:34
• Updated: 28/Jan/24 00:11
• Resolved: 17/Nov/22 09:51

Description

The current implementation converts the value from int to float, causing the compareAndSet method to get stuck.

private final boolean compareAndSet(float expect, float update) {
  return value.compareAndSet(Float.floatToIntBits(expect),
      Float.floatToIntBits(update));
}

private void incr(float delta) {
  while (true) {
    float current = value.get();
    float next = current + delta;
    if (compareAndSet(current, next)) {
      setChanged();
      return;
    }
  }
} 

 

Perhaps it could be:

private void incr(float delta) {
  while (true) {
    float current = Float.intBitsToFloat(value.get());
    float next = current + delta;
    if (compareAndSet(current, next)) {
      setChanged();
      return;
    }
  }
} 

 

The unit test looks like this

MutableGaugeFloat mgf = new MutableGaugeFloat(Context,3.2f);
assertEquals(3.2f, mgf.value(), 0.0);
mgf.incr();
assertEquals(4.2f, mgf.value(), 0.0); 

 

Issue Links

• links to: GitHub Pull Request #4823