stan/jdk-24
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

8293872: Make runtime/Thread/ThreadCountLimit.java more robust

Browse Source 
Reviewed-by: dholmes, adinn
This commit is contained in:
Aleksey Shipilev 2022-09-26 12:44:04 +00:00
parent 2be315877b
commit 36b61c5d7e
1 changed files with 31 additions and 28 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

59
test/hotspot/jtreg/runtime/Thread/ThreadCountLimit.java
View File

@ -1,5 +1,5 @@
/*
* Copyright (c) 2020, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2020, 2022, 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
@ -25,7 +25,7 @@
* @test
* @summary Stress test that reaches the process limit for thread count, or time limit.
* @key stress
* @run main ThreadCountLimit
* @run main/othervm -Xmx1g ThreadCountLimit
*/
import java.util.concurrent.CountDownLatch;
@ -36,36 +36,18 @@ public class ThreadCountLimit {
static final int TIME_LIMIT_MS = 5000; // Create as many threads as possible in 5 sec
static class Worker extends Thread {
private final int index;
private final CountDownLatch startSignal;
Worker(int index, CountDownLatch startSignal) {
this.index = index;
Worker(CountDownLatch startSignal) {
this.startSignal = startSignal;
}
@Override
public void run() {
if ((index % 250) == 0) {
System.out.println("INFO: thread " + index + " waiting to start");
}
try {
startSignal.await();
} catch (InterruptedException e) {
throw new Error("Unexpected: " + e);
}
setName(String.valueOf(index));
Thread.yield();
if (index != Integer.parseInt(getName())) {
throw new Error("setName/getName failed!");
}
if ((index % 250) == 0) {
System.out.println("INFO: thread " + getName() + " working");
throw new Error("Unexpected", e);
}
}
}
@ -74,27 +56,37 @@ public class ThreadCountLimit {
CountDownLatch startSignal = new CountDownLatch(1);
ArrayList<Worker> workers = new ArrayList<Worker>();
boolean reachedTimeLimit = false;
boolean reachedNativeOOM = false;
int countAtTimeLimit = -1;
int countAtNativeOOM = -1;
// This is dangerous loop: it depletes system resources,
// so doing additional things there that may end up allocating
// Java/native memory risks failing the VM prematurely.
// Avoid doing unnecessary calls, printouts, etc.
int count = 1;
long start = System.currentTimeMillis();
try {
while (true) {
Worker w = new Worker(count, startSignal);
Worker w = new Worker(startSignal);
w.start();
workers.add(w);
count++;
long end = System.currentTimeMillis();
if ((end - start) > TIME_LIMIT_MS) {
// Windows path or a system with very large ulimit
System.out.println("INFO: reached the time limit " + TIME_LIMIT_MS + " ms, with " + count + " threads created");
reachedTimeLimit = true;
countAtTimeLimit = count;
break;
}
}
} catch (OutOfMemoryError e) {
if (e.getMessage().contains("unable to create native thread")) {
// Linux, macOS path
long end = System.currentTimeMillis();
System.out.println("INFO: reached this process thread count limit at " + count + " [" + (end - start) + " ms]");
reachedNativeOOM = true;
countAtNativeOOM = count;
} else {
throw e;
}
@ -107,7 +99,18 @@ public class ThreadCountLimit {
w.join();
}
} catch (InterruptedException e) {
throw new Error("Unexpected: " + e);
throw new Error("Unexpected", e);
}
// Now that all threads have joined, we are away from dangerous
// VM state and have enough memory to perform any other things.
if (reachedTimeLimit) {
// Windows path or a system with very large ulimit
System.out.println("INFO: reached the time limit " + TIME_LIMIT_MS +
" ms, with " + countAtTimeLimit + " threads created");
} else if (reachedNativeOOM) {
System.out.println("INFO: reached this process thread count limit with " +
countAtNativeOOM + " threads created");
}
}
}