Re: 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.hol...@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