org.mmtk.plan.semispace.gcspy

Class SSGCspyCollector

java.lang.Object

org.mmtk.plan.CollectorContext

org.mmtk.plan.ParallelCollector

org.mmtk.plan.SimpleCollector

org.mmtk.plan.StopTheWorldCollector

org.mmtk.plan.semispace.SSCollector

org.mmtk.plan.semispace.gcspy.SSGCspyCollector

public class SSGCspyCollector
extends SSCollector

This class implements per-collector thread behavior and state for the SSGCspy plan.

See SSGCspy for an overview of the GC-spy mechanisms.

See Also:

SSCollector, SSGCspy, SSGCspyMutator, StopTheWorldCollector, CollectorContext, SimplePhase

Field Summary

Fields

Modifier and Type	Field and Description
private static boolean	DEBUG

Fields inherited from class org.mmtk.plan.semispace.SSCollector

los, ss, trace

Fields inherited from class org.mmtk.plan.SimpleCollector

sanityLocal

Fields inherited from class org.mmtk.plan.ParallelCollector

group

Fields inherited from class org.mmtk.plan.CollectorContext

log

Constructor Summary

Constructors

Constructor and Description
SSGCspyCollector() Constructor

Method Summary

Modifier and Type	Method and Description
protected void	checkAllDriversForRootAddress(Address addr) Pass a root to all drivers.
void	collectionPhase(short phaseId, boolean primary) Perform a (local) collection phase.
private void	debugSpaces(CopySpace scannedSpace) Prints some debugging info.
private LinearSpaceDriver	fromSpaceDriver()
private void	gcspyGatherData(int event) Gather data for GCspy for the semispaces only.
private static SSGCspy	global()
(package private) void	resetRootStreams() Reset all root streams.
private LinearSpaceDriver	toSpaceDriver()

Methods inherited from class org.mmtk.plan.semispace.SSCollector

allocCopy, getCurrentTrace, isSemiSpaceObject, postCopy

Methods inherited from class org.mmtk.plan.StopTheWorldCollector

collect, concurrentCollect, concurrentCollectionPhase

Methods inherited from class org.mmtk.plan.ParallelCollector

parallelWorkerCount, parallelWorkerOrdinal, park, rendezvous, run

Methods inherited from class org.mmtk.plan.CollectorContext

copyCheckAllocator, getId, getLog, initCollector

Methods inherited from class java.lang.Object

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

Field Detail

DEBUG

private static final boolean DEBUG

See Also:

Constant Field Values

Constructor Detail

SSGCspyCollector

public SSGCspyCollector()

Constructor

Method Detail

collectionPhase

public final void collectionPhase(short phaseId,
                                  boolean primary)

Perform a (local) collection phase. Before a collection, we need to discover

• the tospace objects copied by the collector in the last GC cycle
• the semispace objects allocated since by the mutator.
• all immortal objects allocated by the mutator
• all large objects allocated by the mutator

After the semispace has been copied, we need to discover

• the tospace objects copied by the collector
• all immortal objects allocated by the mutator
• all large objects allocated by the mutator

Overrides:

collectionPhase in class SSCollector

Parameters:

phaseId - The unique phase identifier

primary - Should this thread be used to execute any single-threaded local operations?

gcspyGatherData

private void gcspyGatherData(int event)

Gather data for GCspy for the semispaces only.

This method sweeps the semispace under consideration to gather data. Alternatively and more efficiently, 'used space' can obviously be discovered in constant time simply by comparing the start and the end addresses of the semispace. However, per-object information can only be gathered by sweeping through the space and we do this here for tutorial purposes.

Parameters:

event - The event, either BEFORE_COLLECTION, SEMISPACE_COPIED or AFTER_COLLECTION

debugSpaces

private void debugSpaces(CopySpace scannedSpace)

Prints some debugging info.

Parameters:

scannedSpace - the space that was scanned

resetRootStreams

void resetRootStreams()

Reset all root streams.

checkAllDriversForRootAddress

protected void checkAllDriversForRootAddress(Address addr)

Pass a root to all drivers.

Parameters:

addr - The Address of the object to be checked

global

private static SSGCspy global()

Returns:

The active global plan as an SSGCspy instance.

toSpaceDriver

private LinearSpaceDriver toSpaceDriver()

Returns:

the driver for toSpace

fromSpaceDriver

private LinearSpaceDriver fromSpaceDriver()

Returns:

the driver for fromSpace