Hi, Maybe this should go on serviceability-dev as well.
Thanks,
Coleen

On 5/22/18 3:24 PM, Markus Gronlund wrote:
Greetings,

Kindly asking for reviews for the following change:

Bug: https://bugs.openjdk.java.net/browse/JDK-8203321
Webrev: http://cr.openjdk.java.net/~mgronlun/8203321/webrev00/

Summary:

For some context about what this is about, please see this (now) relatively old 
issue: https://bugs.openjdk.java.net/browse/JDK-8019921

The porting work that brought this code from closed to open were optimistic in that the 
following PDH query,  "\Process(java#n)\ID Process", performed relatively 
stable on Windows 10.
An invariant was added in that your ID Process query would never return an 
index that was lower than the index at construction.

During testing, it was discovered that this invariant did not hold, especially when 
running on Windows Server 2012 R2 and there is a high churn rate with many processes with 
the same base name ("java#") starting and stopping (stressing PDH list of 
processes).

We have to reinsert back the original code that handled the case where the PDH 
process list is not stable (that were originally put in place with JDK-8019921).
The defensive logic is located at lines 418 - 422.

I had to rework some related code to make some room for this as well as to keep 
track of the previous process index.

Thanks
Markus

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