JEP 167

[Mario Torre]

On Fri, 2014-05-16 at 09:12 +0200, Staffan Larsen wrote:

Hello Staffan,

Thanks for the quick reply.

> JEP 167 is done and should be in the completed state. I’ll see if I
> can get that updated. The relevant bug (with change set information)
> is: https://bugs.openjdk.java.net/browse/JDK-8005849.

Great, yeah, updating the page seems a good idea :)

> For seeing what instrumentation has been added, take a look at
> src/share/vm/trace/trace.xml which lists all instrumentation points.
> To enable trace output in OpenJDK, run with q (although running Java
> Flight Recorder [1] from Java Mission Control [2] provides a much
> better user experience).

I see, thanks. It would be nice to also have some documentation how to
get those traces, for instance, assuming I want to turn on/off a
specific trace, and I want to attach my own agent, how would I do this?

I guess I can figure it out somehow from the code, but it's not obvious
if those traces can be used other than via the target vm printing stuff.

I understand Flight Recorded is able to access this information, but
what if I want to write my own agent? Is this accessed via JVMTI, or
JMX, or is there another way (perhaps less expensive)?

A final question, do you know the impact when instrumentation is turned
on (I can do my one testing, but maybe there are some official numbers
around already :)?

> Regarding the broken links, it looks like the
> http://opengrok.neojava.org is no longer what it used to be. In
> general, page you refer to has not been updated for several years...

Hmm, I believe this should be updated as well, it's a pretty important
page and I think the first place anyone interested in serviceability
would look at, what do you think?

Cheers,
Mario