Greetings,
Kindly asking for reviews for the following changeset. Bug: https://bugs.openjdk.java.net/browse/JDK-8056049 Webrev: http://cr.openjdk.java.net/~mgronlun/8056049/webrev01/ Description: The issue is Windows specific. And the problem relates to using the Performance Data Helper API (PDH), more specifically how to use the "Process" PDH object in PDH queries: // code comment extract /* * Working against the Process object and it's related counters is inherently problematic * when using the PDH API: * * For PDH, a process is not primarily identified by it's process id, * but with a sequential number, for example \Process(java#0), \Process(java#1), .... * The really bad part is that this list is reset as soon as one process exits: * If \Process(java#1) exits, \Process(java#3) now becomes \Process(java#2) etc. * * The PDH query api requires a process identifier to be submitted when registering * a query, but as soon as the list resets, the query is invalidated (since the name * changed). * * Solution: * The #number identifier for a Process query can only decrease after process creation. * * Therefore we create an array of counter queries for all process object instances * up to and including ourselves: * * Ex. we come in as third process instance (java#2), we then create and register * queries for the following Process object instances: * java#0, java#1, java#2 * * currentQueryIndexForProcess() keeps track of the current "correct" query * (in order to keep this index valid when the list resets from underneath, * ensure to call getCurrentQueryIndexForProcess() before every query involving * Process object instance data). */ I have already fixed this in the VM as of https://bugs.openjdk.java.net/browse/JDK-8019921 In the process of fixing this issue now in the JDK, I realized that the previous implementation of using PDH in the JDK was a bit convoluted - especially if you would like to reuse functionality / add new counters. Therefore this change also includes an overall rewrite of the how the JDK will interface with the PDH library, a rewrite of which (hopefully) improves both readability and extensibility. I can do a code walkthrough live if anyone is interested to know the exact details of this change. Testing completed : Testset SVC (includes jdk_instrument, jdk_management, jdk_jmx, jdk_jdi) Thanks in advance Markus
