one.profiler

Class AsyncProfiler

java.lang.Object

one.profiler.AsyncProfiler

All Implemented Interfaces:

AsyncProfilerMXBean

public class AsyncProfiler
extends Object
implements AsyncProfilerMXBean

Java API for in-process profiling. Serves as a wrapper around async-profiler native library. This class is a singleton. The first call to getInstance() initiates loading of libasyncProfiler.so.

Method Summary

Modifier and Type	Method and Description
String	dumpCollapsed(Counter counter) Dump profile in 'collapsed stacktraces' format
String	dumpFlat(int maxMethods) Dump flat profile, i.e.
String	dumpTraces(int maxTraces) Dump collected stack traces
String	execute(String command) Execute an agent-compatible profiling command - the comma-separated list of arguments described in arguments.cpp
static AsyncProfiler	getInstance()
static AsyncProfiler	getInstance(String libPath)
long	getSamples() Get the number of samples collected during the profiling session
String	getVersion() Get profiler agent version, e.g.
void	resume(String event, long interval) Start or resume profiling without resetting collected data.
void	start(String event, long interval) Start profiling
void	stop() Stop profiling (without dumping results)

Methods inherited from class java.lang.Object

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

Method Detail

getInstance

public static AsyncProfiler getInstance()

getInstance

public static AsyncProfiler getInstance(String libPath)

start

public void start(String event,
                  long interval)
           throws IllegalStateException

Start profiling

Specified by:

start in interface AsyncProfilerMXBean

Parameters:

event - Profiling event, see Events

interval - Sampling interval, e.g. nanoseconds for Events.CPU

Throws:

IllegalStateException - If profiler is already running

resume

public void resume(String event,
                   long interval)
            throws IllegalStateException

Start or resume profiling without resetting collected data. Note that event and interval may change since the previous profiling session.

Specified by:

resume in interface AsyncProfilerMXBean

Parameters:

event - Profiling event, see Events

interval - Sampling interval, e.g. nanoseconds for Events.CPU

Throws:

IllegalStateException - If profiler is already running

stop

public void stop()
          throws IllegalStateException

Stop profiling (without dumping results)

Specified by:

stop in interface AsyncProfilerMXBean

Throws:

IllegalStateException - If profiler is not running

getSamples

public long getSamples()

Get the number of samples collected during the profiling session

Specified by:

getSamples in interface AsyncProfilerMXBean

Returns:

Number of samples

getVersion

public String getVersion()

Get profiler agent version, e.g. "1.0"

Specified by:

getVersion in interface AsyncProfilerMXBean

Returns:

Version string

execute

public String execute(String command)
               throws IllegalArgumentException,
                      IOException

Execute an agent-compatible profiling command - the comma-separated list of arguments described in arguments.cpp

Specified by:

execute in interface AsyncProfilerMXBean

Parameters:

command - Profiling command

Returns:

The command result

Throws:

IllegalArgumentException - If failed to parse the command

IOException - If failed to create output file

dumpCollapsed

public String dumpCollapsed(Counter counter)

Dump profile in 'collapsed stacktraces' format

Specified by:

dumpCollapsed in interface AsyncProfilerMXBean

Parameters:

counter - Which counter to display in the output

Returns:

Textual representation of the profile

dumpTraces

public String dumpTraces(int maxTraces)

Dump collected stack traces

Specified by:

dumpTraces in interface AsyncProfilerMXBean

Parameters:

maxTraces - Maximum number of stack traces to dump. 0 means no limit

Returns:

Textual representation of the profile

dumpFlat

public String dumpFlat(int maxMethods)

Dump flat profile, i.e. the histogram of the hottest methods

Specified by:

dumpFlat in interface AsyncProfilerMXBean

Parameters:

maxMethods - Maximum number of methods to dump. 0 means no limit

Returns:

Textual representation of the profile