RFR: JDK-8134161 JVM is creating too many GC helper threads on T7/M7 linux/sparc platform

[Daniel D. Daugherty]

On 8/31/15 1:27 PM, Gerald Thornbrugh wrote:
> Hi,
>
> There is a Linux/SPARC related issue in JDK8 and JDK9 where hotspot 
> does not identify a SPARC T7/M7
> platform correctly.  Because hotspot does not identify the T7/M7 
> platform correctly it uses the default
> number of GC helper threads which is twice the number that is should 
> use.  The fix adds code to
> detect a M series platform from the /proc/cpuinfo file and sets the 
> correct CPU features.  Setting the
> correct features allow the correct number of GC helper threads to be 
> allocated.
>
> The fix only impacts the Linux/SPARC code and does not impact any 
> other platform/OS combination.
>
> I have completed successful JPRT test runs for each set of changes and 
> have also verified that the change
> addresses the issue on Linux/SPARC M series hardware.
>
> Here is the bug:
>
> https://bugs.openjdk.java.net/browse/JDK-8134161
>
> Here is the JDK9 webrev:
>
> http://cr.openjdk.java.net/~gthornbr/8134161/webrev/ 
> <http://cr.openjdk.java.net/%7Egthornbr/8134161/webrev/>

src/os_cpu/linux_sparc/vm/vm_version_linux_sparc.cpp
     No comments.


> Here is the JDK8 webrev:
>
> http://cr.openjdk.java.net/~gthornbr/8134674/webrev/ 
> <http://cr.openjdk.java.net/%7Egthornbr/8134674/webrev/>

src/os_cpu/linux_sparc/vm/vm_version_linux_sparc.cpp
     No comments.

Thumbs up on both webrevs.

Dan



>
> Please let me know if you have any questions or concerns.
>
> Thanks,
>
> Gerald Thornbrugh