Nashorn and JVMTI

[Bernd]

Hello David,

Do you want to optimize the JVM settings before challenging V8 or do you
hope to get absolute measurements with the profiler to show off?

Because I would advice against using profilers for anything besides
optimizations, finding hotspots and doing before/after comparision or
trends.

For the shootout an externally driven metric (req/s, 99%th service times)
is a guess better. And particular on bigger machines (which I would expect
to be the NodeJS bottleneck - not sure if Avatar.JS does this better).

Gruss
Bernd
Am 25.09.2014 23:24 schrieb "David P. Caldwell" <
david at code.davidpcaldwell.com>:

> Team,
>
> When I attempt to connect the NetBeans profiler (which I understand to
> be essentially the same as jvisualvm) to a Nashorn embedding, I get an
> error (JVMTI error 62) for essentially every class that relates to
> scripting, including the dynalink stuff and Nashorn itself, as well as
> generated classes named NashornJavaAdapter.
>
> If I persist through all of this (or filter them out of being
> profiled, or turn on -Xverify:none), I end up with profiling data that
> doesn't involve the JavaScript code at all; it basically treats the
> call to eval() as atomic.
>
> Do you guys do this stuff? My customers are constantly objecting to
> the "fact" that running Java on the JVM is going to be a terrible
> idea, performance-wise -- especially compared to Node, which they
> believe is lightning fast -- and I am having difficulty generating
> data on this point.
>
> More generally, of course, profiling is a normal and necessary
> development activity. I wrote a Java agent for Rhino that mangled the
> classes using Javassist to wrap all JavaScript function invocations in
> instrumented methods, but I'm not clear on (a) whether that's
> necessary, or (b) how it would work given the Nashorn implementation
> is probably using constructs I don't yet understand. But if that's the
> route, let me know and give me a pointer or two and I'll be on my way.
>
> -- David P. Caldwell
> http://www.davidpcaldwell.com/
>