GC parameters used by a lot of projects are handed down like traditions for 
years, even spreading to others. They're almost never re-evaluated, which means 
they might actually lose out on new performance improvements, or worse, might 
even cause performance regressions.

Most parameters in the Overtone lib for instance have been the default for 
quite some time (ParNew GC, TLAB). Where restricting New Gen might be a good 
idea to reduce new gen GC latency, it can cause unwanted promotions, longer 
tenured GC's and in the end heap fragmentation resulting in a full defrag gc 
that can take 10s of seconds.

Defaults are there for a reason, to take care of most situations. Any settings 
other than the three default Garbage Collectors (Default for shortest time to 
finish, CMS for shortest pause , G1 for short pauses but long running times) 
and at most a pause hint for their heuristics means you're entering 
case-specific  territory and should be treating it so.

This means realistic benchmarking, profiling and comparisons between different 
settings. I'd treat any JVM product or library with more than 2 GC parameters 
with care, because if they need so much tweaking as their default, you can be 
sure to need both a good understanding of their inner workings and JVM memory 
managent as well to keep them performing in your specific case.

-- 
You received this message because you are subscribed to the Google
Groups "Clojure" group.
To post to this group, send email to clojure@googlegroups.com
Note that posts from new members are moderated - please be patient with your 
first post.
To unsubscribe from this group, send email to
clojure+unsubscr...@googlegroups.com
For more options, visit this group at
http://groups.google.com/group/clojure?hl=en
--- 
You received this message because you are subscribed to the Google Groups 
"Clojure" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to clojure+unsubscr...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.

Reply via email to