On the way to perfect computing

Recently we needed to resolve some performance issues, so I looked for the tool and started in eclipse plugin list. Luckily I found a one.

You need to have binary dump of your heap in order to load it there and analyse. You can find how to do that here

But this tool is not a silver bullet, and sometimes analysing text dump is sufficient and more interesting(low level stuff), depending on what you exactly need.

On VM side I found the following useful params:

• Make GC talk to us: -verbose:gc
• Show us when garbage collection cycles happen: -XX:+PrintGCTimeStamps
• If some 3rd library introduced CPU bound by querying System.gc(), make them calm:  -XX:+DisableExplicitGC
• Dump heap on error:-XX:+HeapDumpOnOutOfMemoryError
• Specify dump  info you are interested in: -agentlib:hprof=heap=sites,cpu=samples, file=/home/user/user.hprof, cutoff=0,lineno=y,thread=y,doe=n “