13 Aug
2009
13 Aug
'09
9:24 p.m.
The latest Sun JDK 6 <http://java.sun.com/javase/6/webnotes/6u14.html> has
optional performance optimization for threading. Since Xwiki running in a
web-container is thread-intensive, I'm wondering whether
performance improvements like Escape
Analysis<http://en.wikipedia.org/wiki/Escape_analysis> will
be noticed for Xwiki. How about for its increasing amount of work happening
out of Groovy scripts?
Much attention has been given by Sun, IBM, BEA and others to optimize lock
management and synchronization in their respective
Java 6 virtual machine
offerings. Features like biased locking, lock coarsening, lock elision by
escape analysis and adaptive spin locking are all designed to increase
concurrency by allowing more effective sharing amongst application threads.
http://www.infoq.com/articles/java-threading-optimizations-p1
http://www.infoq.com/articles/java-threading-optimizations-p2
http://blog.xebia.com/2007/12/21/did-escape-analysis-escape-from-java-6/
http://blog.xebia.com/2009/02/18/jvm-threading-optimizations-revisited/
http://blog.juma.me.uk/2008/12/17/objects-with-no-allocation-overhead/
<http://blog.xebia.com/2007/12/21/did-escape-analysis-escape-from-java-6/>
http://java.dzone.com/articles/escape-analysis-java-6-update
<http://java.dzone.com/articles/escape-analysis-java-6-update>
Niels
http://nielsmayer.com
PS: I need to try this experiment again with the non-early access version
http://nielsmayer.com/xwiki/bin/view/fedora10/64bitJavaAppletIn64BitFirefox…
PPS: in clojure land (will this also apply to Groovy?)
http://www.mail-archive.com/clojure@googlegroups.com/msg17221.html
I'm
getting a very significant performance improvement by adding a couple
of JVM
parameters (using jdk 1.6.0_14). They are: -XX:+DoEscapeAnalysis
-XX:+UseBiasedLocking (I think the -server flag is
required for those two
flags to do anything).
...
My runtime with n = 5,000,000 goes from ~7.5 seconds
to ~4.5 seconds.
...
I actually just confirmed that, on my computer at least, those flags have
basically no effect on the java version and a big
difference on the clojure
one.
...
-XX:+AggressiveOpts improves another 5-10%.