Hi Robin,
Saving useful information about failures during shutdown is useful.
Can the shutdown of JFR be put off? Is the use of shutdown hook still
necessary?
Thanks, Roger
On 2/8/2018 10:50 AM, Robin Westberg wrote:
Hi David,
On 8 Feb 2018, at 04:28, David Holmes <david.hol...@oracle.com> wrote:
...
I had an initial look through this.
To be honest I don't like it. We seem to have to record little bits of
information all over the place just so they can be reported by the shutdown
event. It seems untidy. :(
Can you rename _starting_thread to _main_thread please. The use of "starting"
in thread.hpp/cpp is really a naming anomaly. The main thread is the thread that loads
the JVM. And that would be consistent with set_exception_in_main_thread.
Though why do we care if the main thread exited with an unhandled exception? And if we do
care, why do we only care when the shutdown reason is ""No remaining non-daemon Java
threads"?
I don't like the need to add os::get_abort_exit_code. Do we really need it?
What useful information does it convey?
Right, almost all the runtime changes are made in order to try to figure out
what the process exit code from the launcher will eventually be. For example,
the launcher returns 1 if the main thread exited with an unhandled exception,
but 0 otherwise. But I actually agree that this information is probably only of
marginal use (it could always be captured from wherever Java is launched if
someone really wants it), so it is perhaps not worth the trouble.
Discussed it a bit with Erik Gahlin, and perhaps the best option here is to
simply remove the status code field from the event, that would simplify things
and make the code you mention above go away.
It is unfortunate that you need to add beforeHalt to deal with the event
mechanism itself being turned off (?) by a shutdown hook. That would seem to
potentially lose a lot of event information given hooks can run in arbitrary
order and execute arbitrary Java code. And essentially you end up recording the
initial reason shutdown started, though potentially it could end up terminating
for a different reason.
In this case I think it actually conveys useful information if you are trying
to diagnose an unexpected shutdown. It should be useful to find the initial
request of an orderly shutdown, even if something else happens during the
shutdown sequence like a finalizer calling exit (in which case you could
possibly end up with two shutdown events, but both may contain interesting
information).
Best regards,
Robin
Let's see what others think ...
Thanks,
David
On 8/02/2018 1:18 AM, Robin Westberg wrote:
Hi all,
Please review the following change that adds an event-based tracing event that
is generated when the VM shuts down. The intent is to capture shutdowns that
occur after the VM has been properly initialized (as initialization problems
would most likely mean that the tracing framework hasn’t been properly started
either).
Issue: https://bugs.openjdk.java.net/browse/JDK-8041626
Webrev: http://cr.openjdk.java.net/~rwestberg/8041626/webrev.00/
Testing: hs-tier1,hs-tier2,jdk-tier1,jdk-tier2
Best regards,
Robin
