On 13/05/2018 4:10 AM, Kirk Pepperdine wrote:
On May 10, 2018, at 11:26 AM, Thomas Stüfe <[email protected]> wrote:
On Thu, May 10, 2018 at 9:13 AM, Kirk Pepperdine
<[email protected]> wrote:
The stacking at the safe point would be a huge win. Right now thread dump
consistency can really confuse people as the tooling will show two threads
owning the same lock at seemingly the same time. Reality, it’s just that people
didn’t realize you get a safe point for each thread therefor there is motion in
the system as you’re collecting the data.
I am a bit confused. What tooling are you talking about?
jstack. I’ve not seen it with jcmd. But I often see 2 threads holding the same
lock at the “same time” which is of course non-sense. I can dig one up for you
if you’re still confused.
Please do. That seems more likely to be incorrect reporting to me ... I
seem to recall at least one still open issue in this area ...
Thanks,
David
-----
As an aside, it’s amazing how many dev’s aren’t aware of jcmd. Just yesterday
after my session at Devoxx I had someone ask me about using jfr from the
command line, many in that session had not seen jcmd before. The feedback was,
wow, this is very useful and I wished I had of known about it earlier.
Yes, jcmd is quite useful. I also really like the simple design, which
is by default up- and downward compatible (so you can talk to any VM,
new, old, it should not matter). That is just good design. We - Sap -
work to extend jcmd, to help our support folks. E.g. the whole new
VM.metaspace command chain.
And simple it is….well done!!!
— Kirk
