Package com.oracle.truffle.tools.profiler

Class MemoryTracer

java.lang.Object
com.oracle.truffle.tools.profiler.MemoryTracer
All Implemented Interfaces:
Closeable, AutoCloseable
public final class MemoryTracer extends Object implements Closeable
Implementation of a memory tracing profiler for Truffle languages built on top of the Truffle instrumentation framework.

The tracer counts how many times each of the elements of interest (e.g. functions, statements, etc.) allocates memory, as well as meta data about the allocated object. It keeps a shadow stack during execution, and listens for allocation events. On each event, the allocation information is associated to the top of the stack.

NOTE: This profiler is still experimental with limited capabilities.

Usage example: 

Context context = Context.create();

MemoryTracer tracer = MemoryTracer.find(context.getEngine());
tracer.setCollecting(true);
context.eval("...", "...");
tracer.setCollecting(false);
// rootNodes is the recorded profile of the execution in tree form.

tracer.close();
// Prints information about the roots of the tree.
for (ProfilerNode<MemoryTracer.Payload> node : tracer.getRootNodes()) {
    final String rootName = node.getRootName();
    final long allocCount = node.getPayload().getTotalAllocations();
}
Since:
0.30

  • Method Details

    • find

      public static MemoryTracer find(org.graalvm.polyglot.Engine engine)
      Finds MemoryTracer associated with given engine.
      Parameters:
      engine - the engine to find debugger for
      Returns:
      an instance of associated MemoryTracer
      Since:
      19.0

    • setCollecting

      public void setCollecting(boolean collecting)
      Controls whether the tracer is collecting data or not.
      Parameters:
      collecting - the new state of the tracer.
      Since:
      0.30

    • isCollecting

      public boolean isCollecting()
      Returns:
      whether or not the sampler is currently collecting data.
      Since:
      0.30

    • getRootNodes

      public Collection<ProfilerNode<MemoryTracer.Payload>> getRootNodes()
      Returns:
      The roots of the trees representing the profile of the execution.
      Since:
      0.30

    • getThreadToNodesMap

      public Map<Thread,Collection<ProfilerNode<MemoryTracer.Payload>>> getThreadToNodesMap()
      Returns:
      The roots of the trees representing the profile of the execution per thread.
      Since:
      19.0

    • clearData

      public void clearData()
      Erases all the data gathered by the tracer.
      Since:
      0.30

    • hasData

      public boolean hasData()
      Returns:
      whether or not the sampler has collected any data so far.
      Since:
      0.30

    • getStackLimit

      public int getStackLimit()
      Returns:
      size of the shadow stack
      Since:
      0.30

    • setStackLimit

      public void setStackLimit(int stackLimit)
      Sets the size of the shadow stack. Whether or not the shadow stack grew more than the provided size during execution can be checked with hasStackOverflowed()
      Parameters:
      stackLimit - the new size of the shadow stack
      Since:
      0.30

    • hasStackOverflowed

      public boolean hasStackOverflowed()
      Returns:
      was the shadow stack size insufficient for the execution.
      Since:
      0.30

    • setFilter

      public void setFilter(com.oracle.truffle.api.instrumentation.SourceSectionFilter filter)
      Sets the filter for the sampler. This allows the sampler to observe only parts of the executed source code.
      Parameters:
      filter - The new filter describing which part of the source code to sample
      Since:
      0.30

    • close

      public void close()
      Closes the tracer for fuhrer use, deleting all the gathered data.
      Specified by:
      close in interface AutoCloseable
      Specified by:
      close in interface Closeable
      Since:
      0.30