Please review the change that improves performance of ThreadMXBean MXBean methods returning the information for specific threads. The change introduces the thread table that uses ConcurrentHashTable to store one-to-one the mapping between the thread ids and JavaThread objects and replaces the linear search over the thread list in ThreadsList::find_JavaThread_from_java_tid(jlong tid) method with the lookup in the thread table.
Testing: Mach5 tier1,tier2 and tier3 tests successfully passed. Webrev: https://cr.openjdk.java.net/~dtitov/8185005/webrev.01/ Bug: https://bugs.openjdk.java.net/browse/JDK-8185005 Thanks! Best regards, Daniil
