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

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	MemoryTracer.AllocationEventInfo Stores informatino about a single AllocationEvent.
static class	MemoryTracer.Payload Used as a template parameter for ProfilerNode.

Method Summary

Modifier and Type	Method and Description
void	clearData() Erases all the data gathered by the tracer.
void	close() Closes the tracer for fuhrer use, deleting all the gathered data.
static MemoryTracer	find(org.graalvm.polyglot.Engine engine) Finds MemoryTracer associated with given engine.
Collection<ProfilerNode<MemoryTracer.Payload>>	getRootNodes()
int	getStackLimit()
Map<Thread,Collection<ProfilerNode<MemoryTracer.Payload>>>	getThreadToNodesMap()
boolean	hasData()
boolean	hasStackOverflowed()
boolean	isCollecting()
void	setCollecting(boolean collecting) Controls whether the tracer is collecting data or not.
void	setFilter(com.oracle.truffle.api.instrumentation.SourceSectionFilter filter) Sets the filter for the sampler.
void	setStackLimit(int stackLimit) Sets the size of the shadow stack.

Methods inherited from class java.lang.Object

clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

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 MemoryTracer.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 Closeable

Specified by:

close in interface AutoCloseable

Since:

0.30