RFR(s): 8205582: PPC64: RTM: Fix counter for aborts on nested transactions

[Gustavo Romero]

Hi,

Could the following change be reviewed please?

bug   : https://bugs.openjdk.java.net/browse/JDK-8205582
webrev: http://cr.openjdk.java.net/~gromero/8205582/v1/

It fixes the RTM counter for nested aborts (rtm lock aborts type 5) by
extracting and checking bits in the Transactional Level field of TEXASR
register.

It also fixes the memory conflict counter (rtm lock aborts type 2). Power TM
status register supports two bits to inform two different types of memory
conflict between threads: non-transactional and transactional. According to how
the jtreg RTM tests are designed the memory conflict counter counts
non-transactional conflicts: on TestPrintPreciseRTMLockingStatistics a RTM lock
is held on a static variable while another thread without any synchronization
(non-trasactional) tries to modify the same variable. Hence that small
adjustment satisfies the TestPrintPreciseRTMLockingStatistics making it pass on
Power. The memory conflict counter is not used in any other place besides by the
RTM precise statistics (no decision is made by the JVM based on that amount).

This change partially fixes some failures in
compiler/rtm/print/TestPrintPreciseRTMLockingStatistics.java regarding the
nested and memory conflict abort counters. The remaining issue will be fixed by
aborting on calling JNI (next RFR).


Thank you and best regards,
Gustavo