http://openjdk.java.net/projects/code-tools/jmh/jmh-core/: The jmh is a Java harness for building, running, and analysing nano/micro/macro benchmarks written in Java and other languages targeting the JVM. (Oracle)
  • Aleksey Shipilev (Oracle/Sun, Red Hat)
  • Sergey Kuksenko (Oracle/Sun)
  • Anders Astrand (Oracle/BEA)
  • Staffan Friberg (Oracle/BEA)
  • Henrik Loef (Oracle/BEA) 
/*
 * Copyright (c) 2005, 2013, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
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 */
package org.openjdk.jmh.profile;

import org.openjdk.jmh.infra.BenchmarkParams;
import org.openjdk.jmh.results.BenchmarkResult;
import org.openjdk.jmh.results.Result;

import java.io.File;
import java.util.Collection;


External profiler: profilers to be run outside of JVM.

External profilers usually call external tools to get the performance data.
It is futile to query any internal JVM facilities in external profiler
Java code, because it may not be executed in the benchmarked VM at all.


/**
 * External profiler: profilers to be run outside of JVM.
 *
 * <p>External profilers usually call external tools to get the performance data.
 * It is futile to query any internal JVM facilities in external profiler
 * Java code, because it may not be executed in the benchmarked VM at all.</p>
 */
public interface ExternalProfiler extends Profiler {

    
Prepend JVM invocation with these commands.

Params:
  • params – benchmark parameters used for current launch
Returns:commands to prepend for JVM launch
/**
     * Prepend JVM invocation with these commands.
     *
     * @param params benchmark parameters used for current launch
     * @return commands to prepend for JVM launch
     */
    Collection<String> addJVMInvokeOptions(BenchmarkParams params);

    
Add JVM these options to the run.

Params:
  • params – benchmark parameters used for current launch
Returns:options to add to JVM launch
/**
     * Add JVM these options to the run.
     *
     * @param params benchmark parameters used for current launch
     * @return options to add to JVM launch
     */
    Collection<String> addJVMOptions(BenchmarkParams params);

    
Run this code before starting the trial. This method will execute
before starting the benchmark JVM.

Params:
  • benchmarkParams – benchmark parameters used for current launch
/**
     * Run this code before starting the trial. This method will execute
     * before starting the benchmark JVM.
     *
     * @param benchmarkParams benchmark parameters used for current launch
     */
    void beforeTrial(BenchmarkParams benchmarkParams);

    
Run this code after the trial is done. This method will execute
after benchmark JVM had stopped.

Params:
  • br – benchmark result that was the result of the trial
  • stdOut – file containing the standard output from the benchmark JVM
  • stdErr – file containing the standard error from the benchmark JVM
Returns:profiler results
/**
     * Run this code after the trial is done. This method will execute
     * after benchmark JVM had stopped.
     *
     * @param br benchmark result that was the result of the trial
     * @param stdOut file containing the standard output from the benchmark JVM
     * @param stdErr file containing the standard error from the benchmark JVM
     * @return profiler results
     */
    Collection<? extends Result> afterTrial(BenchmarkResult br, long pid, File stdOut, File stdErr);

    
If target VM communicates with profiler with standard output, this method
can be used to shun the output to console. Profiler is responsible for consuming
the standard output and printing the relevant data from there.

Returns:returns true, if profiler allows harness to print out the standard output
/**
     * If target VM communicates with profiler with standard output, this method
     * can be used to shun the output to console. Profiler is responsible for consuming
     * the standard output and printing the relevant data from there.
     *
     * @return returns true, if profiler allows harness to print out the standard output
     */
    boolean allowPrintOut();

    
If target VM communicates with profiler with standard error, this method
can be used to shun the output to console. Profiler is responsible for consuming
the standard error and printing the relevant data from there.

Returns:returns true, if profiler allows harness to print out the standard errpr
/**
     * If target VM communicates with profiler with standard error, this method
     * can be used to shun the output to console. Profiler is responsible for consuming
     * the standard error and printing the relevant data from there.
     *
     * @return returns true, if profiler allows harness to print out the standard errpr
     */
    boolean allowPrintErr();
}