JConsole can be very useful in seeing what the JVM is doing. <http://java.sun.com/developer/technicalArticles/J2SE/jconsole.html>
On Fri, Jan 16, 2009 at 4:40 PM, Elliott Sprehn <[email protected]> wrote: > The JVM has about a hundred options for fine tuning garbage collection. Have > you tried turning on the JVM GC logging and looking at what it's really > doing? > > - Elliott > > On Jan 16, 2009, at 1:05 PM, Edmund Kohlwey wrote: > >> Good questions! >> >> Right now one of my biggest concerns is actually memory usage. The >> application frequently garbage collects, and despite my attempts to reduce >> memory consumption I still find that the rate of (and penalty incurred by) >> GC'ing is excessive, and may become unacceptable. I realize that there >> probably won't be much that I can do to reduce GC rate, but if a different >> JVM could decrease the penalty that would be of significant value. >> >> Dustin J. Mitchell wrote: >>> >>> "We should forget about small efficiencies, say about 97% of the time: >>> premature optimization is the root of all evil." (Hoare) >>> >>> Ed wrote, "I am ... concerned about performance of the JVM...." Well, >>> JVMs are very slow at some things, and very fast at others. By >>> compiling with gcj, you gain in some areas (to varying degrees over >>> various JVM's) while losing in others (gcj can, in some instances, end >>> up compiling down to a bunch of subroutine calls to implement complex >>> operations, which is a loss over optimized JIT JVMs). >>> >>> So out come the old saws, "what do you mean by performance" and "how >>> are you going to measure it?" That's really the only way to get to >>> the bottom of this question. >>> >>> Dustin >>> >>> >
