Hi Gunter, 

Sounds like a useful enhancement!

Do you have an idea of what the overhead might be? 

Does it work on Mac OS X?

I haven't done a proper review, but you could change the contentType to 
"bits-per-second”. That is what we use for the Network Utilization event which 
reports statistics per interface.

Thanks
Erik

> 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 
> <https://bugs.openjdk.java.net/browse/JDK-8216981>
> 
> Here is a webrev:
> http://cr.openjdk.java.net/~ghaug/webrevs/8216981 
> <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
> 
> 
> 
> 

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