JDK-8029101 : PPC64 (part 211): ordering of Independent Reads of Independent Writes
- Type: Bug
- Component: hotspot
- Sub-Component: runtime
- Affected Version: port-stage-ppc-aix
- Priority: P4
- Status: Resolved
- Resolution: Fixed
- CPU: ppc
- Submitted: 2013-11-25
- Updated: 2017-01-25
- Resolved: 2014-01-22
The Version table provides details related to the release that this issue/RFE will be addressed.
Unresolved : Release in which this issue/RFE will be addressed.
Resolved: Release in which this issue/RFE has been resolved.
Fixed : Release in which this issue/RFE has been fixed. The release containing this fix may be available for download as an Early Access Release or a General Availability Release.
To download the current JDK release, click here.
Unresolved : Release in which this issue/RFE will be addressed.
Resolved: Release in which this issue/RFE has been resolved.
Fixed : Release in which this issue/RFE has been fixed. The release containing this fix may be available for download as an Early Access Release or a General Availability Release.
To download the current JDK release, click here.
| JDK 8 | JDK 9 | Other |
|---|---|---|
8u20Fixed  |
9Fixed |
port-stage-ppc-aixFixed |
Related Reports
|
Blocks :
|
|
|
Relates :
|
Description
Implementation of memory ordering on PPC for volatile/unsafe accesses.
This supports ordering of "Independent Reads of Independent Writes"
as tested by VolatileIRIWTest of the torture test suite:
Example: volatile x=0, y=0
_________ __________ __________ __________
| Thread 0 | | Thread 1 | | Thread 2 | | Thread 3 |
write(x=1) read(x) write(y=1) read(y)
read(y) read(x)
Disallowed: x=1, y=0 y=1, x=0
Solution: This example requires multiple-copy-atomicity. This is only
assured by the sync instruction and if it is executed in the thread
doing the load. Thus we implement volatile read as sync-load-acquire
and omit the sync/MemBarVolatile after the volatile store, as
MemBarVolatile happens to be implemented by sync.
This addresses a similar issue as fix "8012144: multiple SIGSEGVs
fails on staxf" for taskqueue.hpp.
Further this change contains a fix that assures that volatile fields
written in constructors are visible before the reference gets
published.
---------------------------------
This is preparation for PPC64 integration: http://openjdk.java.net/jeps/175
This and following ppc64 changes will go into staging repository first and tested there: http://hg.openjdk.java.net/ppc-aix-port/stage/
http://hg.openjdk.java.net/ppc-aix-port/jdk8/hotspot/file/09f97b967480/ppc_patches/0211_rt-order_reads_of_writes.patch