RFR (M): 8207266: ThreadMXBean::getThreadAllocatedBytes() can be quicker for self thread

[Daniel D. Daugherty]

 > http://cr.openjdk.java.net/~phh/8231211/webrev.00/

The redo bug is 8231209. 8231211 is closed as a dup of 8231210.

Dan


On 9/19/19 9:17 AM, Hohensee, Paul wrote:
> I'll have the default method throw UOE. That's the same as the other default methods do.
>
> The necessary test fix is in test/hotspot/jtreg/vmTestbase/nsk/monitoring/share/server/ServerThreadMXBeanNew.java, which needs a new getCurrentThreadAllocatedBytes method, defined as
>
>      public long getCurrentThreadAllocatedBytes() {
>          return (Long) invokeMethod("getCurrentThreadAllocatedBytes",
>              new Object[] { },
>              new String[] { });
>      }
>
> With this fix, the 134 tests in test/hotspot/jtreg/vmTestbase/nsk/monitoring/ThreadMXBean pass. Preliminary webrev at
>
> http://cr.openjdk.java.net/~phh/8231211/webrev.00/
>
> Is it worth adding getCurrentThreadAllocatedBytes tests to the test/hotspot/jtreg/vmTestbase/nsk/monitoring/ThreadMXBean/GetThreadAllocatedBytes set?
>
> Paul
>
> On 9/18/19, 8:16 PM, "David Holmes" <david.holmes at oracle.com> wrote:
>
>      On 19/09/2019 12:57 pm, Mandy Chung wrote:
>      > On 9/18/19 5:00 PM, Hohensee, Paul wrote:
>      >> They all implement com.sun.management.ThreadMXBean, so adding a
>      >> getCurrentThreadAllocatedBytes broke them. Potential fix is to give it
>      >> a default implementation, vis
>      >>
>      >>      public default long getCurrentThreadAllocatedBytes() {
>      >>          return -1;
>      >>      }
>      >>
>      >
>      > com.sun.management.ThreadMXBean (and other platform MXBeans) is a
>      > "sealed" interface which should only be implemented by JDK.
>      
>      Didn't realize that. I don't recall knowing about PlatformManagedObject.
>      Sealed types will at least allow this to be enforced, though I have to
>      wonder what the tests are doing here.
>      
>      > Unfortunately we don't have the sealed type feature yet.  Yes it needs
>      > to be a default method.  I think it should throw UOE.
>      >
>      >       * @implSpec
>      >       * The default implementation throws {@code
>      > UnsupportedOperationException}.
>      >
>      > The @throw UOE can make it clear that it does not support current thread
>      > memory allocation measurement.
>      
>      Yes that seems a reasonable default if we don't want this to be
>      implemented outside the platform.
>      
>      Thanks,
>      David
>      
>      > Mandy
>      
>