Profiling + Indy

[Charles Oliver Nutter]

FWIW, option 2 (hprof) seems like a no-show on u2b08:

headius at headius-vbox-ubuntu:~/projects/redblack$
JAVA_HOME=~/jdk1.7.0_02/ ../jruby/bin/jruby -X+C
-J-Xrunhprof:cpu=times bm1.rb 20
HPROF ERROR: Unknown constant
[../../../src/share/demo/jvmti/java_crw_demo/java_crw_demo.c:693]
[hprof_init.c:210]
HPROF TERMINATED PROCESS

So I'm stuck with sampling.

- Charlie

On Fri, Oct 14, 2011 at 3:52 AM, Charles Oliver Nutter
<headius at headius.com> wrote:
> I'm looking to get back into JRuby + Indy work now that the heaviest
> conferences are behind me. Part of this involves running larger
> benchmarks where the hot spots may not be apparent at a glance. In
> order to investigate performance on such benchmarks, I will want to do
> some profiling. But what should I use?
>
> For really egregious problems, the sampling profiler (-Xprof) "sort
> of" works. It's grossly inaccurate when there's no stand-out hotspot,
> but if something is incredibly bad it usually shows it. So that's
> option 1.
>
> There's -Xrunhprof:cpu=times, which is more accurate, but the impact
> to running code is enormous, there's no way to filter out
> uninteresting code (like JDK core), and I have no idea if it works
> properly with indy (given that there's ongoing work to make JVMTI +
> indy play nice). That's option 2.
>
> Are either of these options any good? What else do you recommend?
>
> - Charlie
>