Profiling a J2EE Application

[microserf]

Hi

How can I profile a J2EE application? Specifically, I want to be able to see which lines of code in my servlets take the most time to execute.

I have seen people suggest adding logging code to do this, but this is messy (adding code that doesn't need to be there) and time-consuming (if I have to edit all my code just to profile, it might be quicker to make 'educated' guesses as to where the bottlenecks are).

I have also seen people suggest using HTTP-based stress testing to identify bottlenecks; however this will only provide a coarse level of granularity (i.e. it will reveal which pages take a long time---I already know this---I want to see which lines of code are slow).

Ideally I'd prefer to avoid commercial solutions.

Thanks!

 

[Diancecht]

I don't see the point on profiling the code line by line and the only way I see for that is adding code lines with timestamps.

Appart from that, the coarse level is often the only one that will give you any actual performance improvement.

Cheers,
Dian

 

[microserf]

Thanks Dian, but the point of line-by-line profiling is to see which function calls take a long time. An alternative to line-by-line would be to collect profiling data on method calls, but it would be less useful to know that a lot of time is spent in the foo() method than to know that a specific call to foo() takes a long time (particularly if foo() is a standard Java API call rather than one of my algorithms).

While coarse-level profiling will allow me to measure performance improvement, it does not allow one to determine which specific parts of the code need to be optimised---you would still need to make guesses. Ideally you need both.

I have found EJP (

http://ejp.sourceforge.net),

which appears to allow one to profile J2EE applications in a way that is close to what I'm after, so I'll give that a try.

Thanks anyway.

 

[Diancecht]

Good luck then, but I'd recommend you to measure the performance improvement versus the invested time and I think you will see that profiling single methods or code blocks does not compense.

Cheers,
Dian