DTraceAsmProfiler.java
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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package org.openjdk.jmh.profile;
import joptsimple.OptionException;
import joptsimple.OptionParser;
import joptsimple.OptionSpec;
import org.openjdk.jmh.infra.BenchmarkParams;
import org.openjdk.jmh.results.BenchmarkResult;
import org.openjdk.jmh.results.Result;
import org.openjdk.jmh.util.*;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.util.Collection;
import java.util.Collections;
import java.util.Map;
import java.util.TreeMap;
import java.util.concurrent.TimeUnit;
/**
* Mac OS X perfasm profiler based on DTrace "profile-n" provider which samples program counter by timer interrupt.
* Due to DTrace limitations on Mac OS X target JVM cannot be run directly under DTrace control, so DTrace is run separately,
* all processes are sampled and irrelevant samples are filtered out in {@link #readEvents(double, double)} stage.
* Super user privileges are required in order to run DTrace.
* <p>
* If you see a lot of "[unknown]" regions in profile then you are probably hitting kernel code, kernel sampling is not yet supported.
*
* @author Tolstopyatov Vsevolod
* @since 18/10/2017
*/
public class DTraceAsmProfiler extends AbstractPerfAsmProfiler {
private final boolean useSudo;
private final long sampleFrequency;
private volatile String pid;
private volatile Process dtraceProcess;
private OptionSpec<Long> optFrequency;
private OptionSpec<Boolean> optSudo;
public DTraceAsmProfiler(String initLine) throws ProfilerException {
super(initLine, "sampled_pc");
try {
sampleFrequency = set.valueOf(optFrequency);
useSudo = set.valueOf(optSudo);
} catch (OptionException e) {
throw new ProfilerException(e.getMessage());
}
// Check DTrace availability
Collection<String> messages;
if (useSudo) {
messages = Utils.tryWith("sudo", "-n", "dtrace", "-V");
} else {
messages = Utils.tryWith("dtrace", "-V");
}
if (!messages.isEmpty()) {
throw new ProfilerException(messages.toString());
}
}
@Override
public void beforeTrial(BenchmarkParams params) {
super.beforeTrial(params);
}
@Override
public Collection<? extends Result> afterTrial(BenchmarkResult br, long pid, File stdOut, File stdErr) {
if (pid == 0) {
throw new IllegalStateException("DTrace needs the forked VM PID, but it is not initialized");
}
// We cannot use Process.destroy, because it closes the streams right away.
// Instead, deliver TERM by hand and wait for process to gracefully terminate.
long dtracePid = Utils.getPid(dtraceProcess);
if (dtracePid == 0) {
throw new IllegalStateException("Cannot determine dtrace process PID");
}
Collection<String> messages = Utils.tryWith("sudo", "-n", "kill", "-TERM", Long.toString(dtracePid));
if (!messages.isEmpty()) {
throw new IllegalStateException(messages.toString());
}
// Wait for dtrace to finish.
try {
int errcode = dtraceProcess.waitFor();
if (errcode != 0) {
throw new IllegalStateException("Non-zero error code from dtrace: " + errcode);
}
} catch (InterruptedException e) {
throw new IllegalStateException("Interrupted while waiting for profiler to stop");
}
this.pid = String.valueOf(pid);
return super.afterTrial(br, pid, stdOut, stdErr);
}
@Override
public Collection<String> addJVMInvokeOptions(BenchmarkParams params) {
String dtraceLine = "profile-" + sampleFrequency + " /arg1/ { printf(\"%d 0x%lx %d\", pid, arg1, timestamp); ufunc(arg1)}";
if (useSudo) {
dtraceProcess = Utils.runAsync("sudo", "-n", "dtrace", "-n", dtraceLine, "-o", perfBinData.getAbsolutePath());
} else {
dtraceProcess = Utils.runAsync("dtrace", "-n", dtraceLine, "-o", perfBinData.getAbsolutePath());
}
return Collections.emptyList();
}
@Override
public String getDescription() {
return "DTrace profile provider + PrintAssembly Profiler";
}
@Override
protected void addMyOptions(OptionParser parser) {
optFrequency = parser.accepts("frequency",
"Sampling frequency. This is synonymous to profile-#")
.withRequiredArg().ofType(Long.class).describedAs("freq").defaultsTo(1001L);
optSudo = parser.accepts("sudo", "Use sudo to access dtrace.")
.withRequiredArg().ofType(Boolean.class).defaultsTo(true);
}
@Override
protected void parseEvents() {
// Do nothing because DTrace writes text output anyway
}
@Override
protected PerfEvents readEvents(double skipMs, double lenMs) {
long start = (long) skipMs;
long end = (long) (skipMs + lenMs);
try (FileReader fr = new FileReader(perfBinData.file());
BufferedReader reader = new BufferedReader(fr)) {
Deduplicator<MethodDesc> dedup = new Deduplicator<>();
Multimap<MethodDesc, Long> methods = new HashMultimap<>();
Multiset<Long> events = new TreeMultiset<>();
long dtraceTimestampBase = 0L;
String line;
while ((line = reader.readLine()) != null) {
// Filter out DTrace misc
if (!line.contains(":profile")) {
continue;
}
line = line.trim();
line = line.substring(line.indexOf(":profile"));
String[] splits = line.split(" ", 5);
if (splits.length < 2) {
// Suspect completely corrupted line, skip
continue;
}
String sampledPid = splits[1];
if (!sampledPid.equals(pid)) {
continue;
}
// Sometimes DTrace ufunc fails and gives no information about symbols
if (splits.length < 4) {
continue;
}
long timestamp = Long.parseLong(splits[3]);
if (dtraceTimestampBase == 0) {
// Use first event timestamp as base for time comparison
dtraceTimestampBase = timestamp;
continue;
}
long elapsed = timestamp - dtraceTimestampBase;
long elapsedMs = TimeUnit.NANOSECONDS.toMillis(elapsed);
if (elapsedMs < start || elapsedMs > end) {
continue;
}
long address = Long.decode(splits[2]);
events.add(address);
String methodLine = splits[4];
// JIT-compiled code has address instead of symbol information
if (methodLine.startsWith("0x")) {
continue;
}
String symbol = "[unknown]";
String[] methodSplit = methodLine.split("`");
String library = methodSplit[0];
if ("".equals(library)) {
library = "[unknown]";
}
if (methodSplit.length == 2) {
symbol = methodSplit[1];
}
methods.put(dedup.dedup(MethodDesc.nativeMethod(symbol, library)), address);
}
IntervalMap<MethodDesc> methodMap = new IntervalMap<>();
for (MethodDesc md : methods.keys()) {
Collection<Long> longs = methods.get(md);
methodMap.add(md, Utils.min(longs), Utils.max(longs));
}
Map<String, Multiset<Long>> allEvents = new TreeMap<>();
assert requestedEventNames.size() == 1;
allEvents.put(requestedEventNames.get(0), events);
return new PerfEvents(requestedEventNames, allEvents, methodMap);
} catch (IOException e) {
throw new RuntimeException(e);
}
}
@Override
protected String perfBinaryExtension() {
// DTrace produces human-readable txt
return ".txt";
}
}