Async-profiler: Allocation stacktrace incomplete with JRE 9

[aminebag]

Hi,

When I use AsyncProfiler with an Oracle JRE 9 JVM I only get one horizontal level of stacktrace for _alloc_ event using _collapsed_ and/or _svg_ output formats. While, for the same bytecode, I get a complete stacktrace with Oracle JRE 8 JVM.

• Code (compiled with Oracle JDK 8):

  public class AsyncProfilerTest {
  
      public static void main(String[] args) {
          a();
      }
  
      private static void a() {
          for(long i=0;i<Long.MAX_VALUE;i++) {
              System.out.println("a:"+Math.random());
              if(i%100 == 0) b();
              if(i%10 == 0) c();
          }
      }
  
      private static void b() {
          System.out.println("b:"+Math.random());
      }
  
      private static void c() {
          System.out.println("c:"+Math.random());
          if(Math.random()>0.7) d();
      }
  
      private static void d() {
          System.out.println("f:"+Math.random());
      }
  
  }
  

• Profiling command : _./profiler.sh -d 60 -e alloc -f output_heap.svg -o svg pid_

• SVG output with Oracle JRE 8 JVM :
  

• SVG output with Oracle JRE 9 JVM :
  

• Code, Bytecode, Collapsed & SVG : AsyncProfiler_JRE9.zip

Thanks

[apangin]

The same problem as #60.
I've fixed that once, but soon realized that the fix may sometimes crash JVM (#64) and therefore rolled back the changes.
Will solve this properly in #66.

[aminebag]

Thanks for the quick response !

[apangin]

I discovered that AsyncGetCallTrace stack walking has been broken since JDK 8u141 by the following commit in HotSpot:
http://hg.openjdk.java.net/jdk8u/jdk8u/hotspot/rev/9ffa0d7ed932
If I revert this change and recompile JVM, allocation stack traces will return back again.

I will look how to work around this issue.

[apangin]

Re-implemented stack walking for heap and lock profiling.
Now it relies on internal JVM call instead of AsyncGetCallTrace.
This is a rebirth of fe8b437e0f013d5cdf4a37beb237436063537de7, but now JVM implementation is called directly rather than through public JVMTI interface to prevent deadlocks like #64.

Now Allocation profiling should work on all versions of OpenJDK and Oracle JDK starting from JDK 7u45 up to JDK 11 EA+12. Moreover, allocation stack traces are now exact.

[apangin]

I'll be glad to know whether the fix works for you.

[aminebag]

After the fix it works fine with JVM 9 and 10. Thanks !