[RFR]: Per thread IO statistics in JFR

[Alan Bateman]

On 01/02/2019 11:19, Lindenmaier, Goetz wrote:
> :
> To kick in here, too:
> The existing solution tells you which threads spend a lot of time
> in IO operations. This is a good hint to problems in the infrastructure.
> You might just write a few bytes, but still get long delays because the
> disc is too slow or saturated etc.
> The numbers Gunter collects give information about what your
> code intends to do: how much bytes does the code write? Should
> you optimize your application to communicate less?  ... to write
> less to file?
>
> If you have both numbers, you can even better recognize threads
> that wait too long on the network: they write few bytes but still
> spend a lot of time in the calls.
>
> So I see enough arguments to have both metrics.
>
Erik Gahlin put in support in JDK 12 to allow for code in java.base to 
generate JFR events. I think the only user so far is in the security 
area where there are events to log usages of weak crypto. I think this 
is one of the approaches that will need to be looked at as part of the 
exploration on the right way to add serviceability support to the libraries.

-Alan