RFR(S) Contended Locking fast notify bucket (8075171)

[Daniel D. Daugherty]

Greetings,

I've updated the patch for Contended Locking fast notify bucket
based on David H's and Karen's comments.

This work is being tracked by the following bug ID:

     JDK-8075171 Contended Locking fast notify bucket
     https://bugs.openjdk.java.net/browse/JDK-8075171

Here is the webrev URL:

http://cr.openjdk.java.net/~dcubed/8075171-webrev/1-jdk9-hs-rt/

Here is the JEP link:

     https://bugs.openjdk.java.net/browse/JDK-8046133

Testing:

- RBT vm.quick batches (in process)
- JPRT test jobs
- MonitorWaitNotifyStresser micro-benchmark (in process)
- CallTimerGrid stress testing (in process)


The changes in this round are in only four of the files:

src/share/vm/opto/runtime.cpp

   - deleted comment about hashCode() that belongs in a different bucket

src/share/vm/runtime/objectMonitor.cpp

   - add MAX_RECHECK_INTERVAL define for use in ObjectMonitor::EnterI()
   - cleanup recheck interval code
   - ObjectMonitor::INotify() return type is now "void"
   - delete duplicate comments, clarify/rewrite some comments

src/share/vm/runtime/objectMonitor.hpp

   - ObjectMonitor::INotify() return type is now "void"

src/share/vm/runtime/synchronizer.cpp

   - clarify/rewrite comments, add additional comments
   - cleanup variables in ObjectSynchronizer::quick_notify
   - refactor loop to be more clear
   - delete unused enum MaximumRecheckInterval

The easiest way to review the delta is to download the two patch
files and compare them in something like jfilemerge:

http://cr.openjdk.java.net/~dcubed/8075171-webrev/0-jdk9-hs-rt/hotspot.patch
http://cr.openjdk.java.net/~dcubed/8075171-webrev/1-jdk9-hs-rt/hotspot.patch

Dan


On 5/18/15 2:07 PM, Daniel D. Daugherty wrote:
> Greetings,
>
> I have the Contended Locking fast notify bucket ready for review.
>
> The code changes in this bucket are the final piece in the triad
> of {fast-enter, fast-exit, fast-notify} changes. There are no
> macro assembler changes in this bucket (yeah!), but there are
> code review cleanups motivated by comments on other buckets, e.g.,
> changing variables like 'Tally' -> 'tally'.
>
> This work is being tracked by the following bug ID:
>
>     JDK-8075171 Contended Locking fast notify bucket
>     https://bugs.openjdk.java.net/browse/JDK-8075171
>
> Here is the webrev URL:
>
> http://cr.openjdk.java.net/~dcubed/8075171-webrev/0-jdk9-hs-rt/
>
> Here is the JEP link:
>
>     https://bugs.openjdk.java.net/browse/JDK-8046133
>
> Testing:
>
> - Aurora Adhoc RT/SVC baseline batch
> - JPRT test jobs
> - MonitorWaitNotifyStresser micro-benchmark (in process)
> - CallTimerGrid stress testing (in process)
> - Aurora performance testing:
>   - out of the box for the "promotion" and 32-bit server configs
>   - heavy weight monitors for the "promotion" and 32-bit server configs
>     (-XX:-UseBiasedLocking -XX:+UseHeavyMonitors)
>     (in process)
>
> The hang somehow introduced by the "fast enter" bucket is still
> unresolved, but progress is being made. That work is being tracked
> by the following bug:
>
>     JDK-8077392 Stream fork/join tasks occasionally fail to complete
>     https://bugs.openjdk.java.net/browse/JDK-8077392
>
> You'll see a change that re-enables the "fast enter" bucket in this
> webrev, but that change will not be pushed when we're done with the
> review of this bucket unless JDK-8077392 is resolved.
>
> Thanks, in advance, for any comments, questions or suggestions.
>
> Gory details about the changes are below...
>
> Dan
>
>
> 8075171 summary of changes:
>
> src/share/vm/classfile/vmSymbols.hpp
>   - Add do_intrinsic() entries for _notify and _notifyAll
>
> src/share/vm/opto/library_call.cpp
>   - Add optional inline_notify() that is controlled by new
>     '-XX:[+-]InlineNotify' option
>
> src/share/vm/opto/runtime.cpp
> src/share/vm/opto/runtime.hpp
>   - Add OptoRuntime::monitor_notify_C() and
>     OptoRuntime::monitor_notifyAll_C() functions to support
>     the new "fast notify" code paths
>   - Add new OptoRuntime::monitor_notify_Type() to support
>     the above two new functions
>
> src/share/vm/runtime/globals.hpp
>   - Add '-XX:[+-]InlineNotify' option; default option value is
>     enabled (true)
>
> src/share/vm/runtime/objectMonitor.cpp
> src/share/vm/runtime/objectMonitor.hpp
>   - Refactor ObjectMonitor::notify() and ObjectMonitor::notifyAll()
>     into wrappers that call the new ObjectMonitor::INotify()
>   - Add new ObjectMonitor::INotify() to reduce code duplication
>     between "notify" and "notifyAll" code paths
>
> src/share/vm/runtime/sharedRuntime.cpp
>   - Temporarily re-enable the "fast enter" optimization in order
>     to do performance testing. JDK-8077392 is still unresolved,
>     but progress is being made.
>
> src/share/vm/runtime/synchronizer.cpp
> src/share/vm/runtime/synchronizer.hpp
>   - Add ObjectSynchronizer::quick_notify() that implements the
>     new "fast notify" code paths
>   - The new code handles a couple of special cases where the
>     "notify" can be done without the heavy weight slow-path
>     (thread state transitions and other baggage)
>
>