Is there a tool available to profile java applications regarding branch (mis)prediction statistics for if statements? I know VisualVM and JDK Mission Control but did not find such functionality. Answer No such tool exists. It is generally impossible to extract that information from CPU, you can either measure…
Tag: profiling
JVM Getting the largest objects in the heap programmatically
How programmatically (from within the java application/agent) do I get a “live” summary of the largest objects in the heap (including their instances count and size)? Similarly to what Profilers do. For example, here is a screenshot from JProfiler: Usually I used to work with heap dumps in the cas…
Java Flight Recorder – find file descriptor leak
M Java application probably has a file descriptor leak, since I’m getting a Too many open files exception. I’m running my application with JFR, and when I inspect File I/O I barely see any I/O count. Is it possible to use JFR for finding code which open files but not closes them? Answer No, JFR ca…
Profiling Java code changes execution times
I’m trying to optimize my code, but it’s giving me problems. I’ve got this list of objects: There is 1700 objects with unique id (0-1699) and some name, it’s used to decode what type of data I get later on. The method that I try to optimize works like that: This method is called about …
Java VisualVM does not show/list my tomcat java process
I am using jdk64 and my java version is 1.6.0_24. I am running both (Tomcat java process and VisualVM) processes as Administrator on Windows Server 2008. Tomcat is running with -Xmx7196m, where as jvisualvm is running with -Xms24m and -Xmx256m. Could this be the cause? Answer You need to add the JMX parameter…
Memory size in profiling when i try to detect memory leak
I run java program with -Xms512m -Xmx1G -Xss1G. I make profiling to verify the memory, so i Track every 10 object allocations. i observe this figure : My question is, why it display me that 117mo represent 40% while i give 1G to memory ? Answer The graph is a percentage of all allocations, not the heap size. …
VisualVM launcher error
I’m trying to use the Eclipse VisualVM launcher. It seems pretty nice, except that it seems to spawn an instance if VisualVM too late to do any profiling of my application. My application finishes execution before the profiler is even initialized; once it starts up, an error window pops up, saying: cann…