[RFR]: Per thread IO statistics in JFR

[Severin Gehwolf]

cc-ing hotspot-jfr-dev

On Mon, 2019-01-14 at 15:58 +0000, Haug, Gunter wrote:
> Hi All,
> 
> Could I please have a review and possibly some opinions on the
> following enhancement to JFR and the JDK? 
> 
> At SAP we have a per thread IO statistic among our supportability
> enhancements which proved to be very helpful for our support
> engineers. It might be beneficial for JFR as well and would certainly
> help us to drive adoption of OpenJDK.
> 
> The basic idea is simple, we have added fields to the thread class
> where the number of bytes read and written from/to file and network
> are counted in. The newly created JFR events are written periodically
> as for example the ThreadAllocationStatistics event already is.
> 
> In order to collect the data, we have added hooks to the JDK C coding
> calling back into the VM.
> 
> I have opened a bug here:
> https://bugs.openjdk.java.net/browse/JDK-8216981
> 
> Here is a webrev:
> http://cr.openjdk.java.net/~ghaug/webrevs/8216981
> 
> There are no tests yet and the code be a bit nicer in places. We will
> work on this if/when this feature is deemed acceptable.
> 
> Finally, we have an API in our SAP version of the JDK to access this
> data from a Java application. This is used by many SAP applications
> and I think we could add an MXBean in a second step, to provide
> similar functionality.
> 
> Thanks in advance,
> Gunter
> 
> 
> 
>