Latest

Apr
28

GC forensics by example: multi-second pauses and allocation pressure

This post will analyze a Hotspot GC log exhibiting large GC pauses (> 1 min) leading to allocation pressure and system load as a cause of pathological behaviour on Hotspot’s garbage collector.
12 min read
Jan
30

How does the default hashCode() work? (and why does it affect biased locking?)

In which scratching the surface of hashCode() leads to a speleology trip through the JVM source reaching object layout, biased locking, and surprising performance implications of relying on the default hashCode().
11 min read
Aug
28

Contention on sun.misc.Cleaner

I found recently a (dying) JVM with about 10 threads BLOCKED on the sun.misc.Cleaner class instance. This was not the root cause of the failure, but I could learn something by looking into those blocks.
3 min read
Jun
25

How does the JVM change tenuring thresholds, and when?

On a recent Tuesday evening I ran into this 3 year old JVM question in Stack Overflow. GC features and
1 min read