Part of #1260: write a manually run concurrency test to tease out pro…

…blem with pool retention (#1265)

src/test/java/perf/RecyclerPoolTest.java

@@ -0,0 +1,175 @@
+package perf;
+
+import java.io.*;
+import java.nio.charset.StandardCharsets;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Random;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.concurrent.atomic.AtomicLong;
+
+import com.fasterxml.jackson.core.JsonFactory;
+import com.fasterxml.jackson.core.JsonGenerator;
+import com.fasterxml.jackson.core.JsonParser;
+import com.fasterxml.jackson.core.util.BufferRecycler;
+import com.fasterxml.jackson.core.util.JsonRecyclerPools;
+import com.fasterxml.jackson.core.util.RecyclerPool;
+
+/**
+ * High-concurrency test that tries to see if unbounded {@link RecyclerPool}
+ * implementations grow without bounds or not.
+ */
+public class RecyclerPoolTest
+{
+    final static int THREAD_COUNT = 100;
+
+    final static int RUNTIME_SECS = 60;
+
+    private final int _threadCount;
+
+    RecyclerPoolTest(int threadCount) {
+        _threadCount = threadCount;
+    }
+
+    public String testPool(JsonFactory jsonF, int runtimeMinutes)
+        throws InterruptedException
+    {
+        RecyclerPool<BufferRecycler> poolImpl = jsonF._getRecyclerPool();
+
+        final String poolName = poolImpl.getClass().getSimpleName();
+        final ExecutorService exec = Executors.newFixedThreadPool(_threadCount);
+        final AtomicLong calls = new AtomicLong();
+        final long startTime = System.currentTimeMillis();
+        final long runtimeMsecs = TimeUnit.SECONDS.toMillis(runtimeMinutes);
+        final long endtimeMsecs = startTime + runtimeMsecs;
+        final AtomicInteger threadsRunning = new AtomicInteger();
+
+        System.out.printf("Starting test of '%s' with %d threads, for %d seconds.\n",
+                poolImpl.getClass().getName(),
+                _threadCount, runtimeMsecs / 1000L);
+
+        for (int i = 0; i < _threadCount; ++i) {
+            final int id = i;
+            threadsRunning.incrementAndGet();
+            exec.execute(new Runnable() {
+                @Override
+                public void run() {
+                    testUntil(jsonF, endtimeMsecs, id, calls);
+                    threadsRunning.decrementAndGet();
+                }
+            });
+        }
+
+        long currentTime;
+        long nextPrint = 0L;
+        // Print if exceeds threshold (3 x threadcount), otherwise every 2.5 seconds
+        final int thresholdToPrint = _threadCount * 3;
+        int maxPooled = 0;
+
+        while ((currentTime = System.currentTimeMillis()) < endtimeMsecs) {
+            int poolSize;
+
+            if ((poolSize = poolImpl.pooledCount()) > thresholdToPrint
+                    || (currentTime > nextPrint)) {
+                double secs = (currentTime - startTime) / 1000.0;
+                System.out.printf(" (%s) %.1fs, %dk calls; %d threads; pool size: %d (max seen: %d)\n",
+                        poolName, secs, calls.get()>>10, threadsRunning.get(), poolSize, maxPooled);
+                if (poolSize > maxPooled) {
+                    maxPooled = poolSize;
+                }
+                Thread.sleep(100L);
+                nextPrint = currentTime + 2500L;
+            }
+        }
+
+        String desc = String.format("Completed test of '%s': max size seen = %d",
+                poolName, maxPooled);
+        System.out.printf("%s. Wait termination of threads..\n", desc);
+        if (!exec.awaitTermination(2000, TimeUnit.MILLISECONDS)) {
+            System.out.printf("WARNING: ExecutorService.awaitTermination() failed: %d threads left; will shut down.\n",
+                    threadsRunning.get());
+            exec.shutdown();
+        }
+        return desc;
+    }
+
+    void testUntil(JsonFactory jsonF,
+             long endTimeMsecs, int threadId, AtomicLong calls)
+    {
+        final Random rnd = new Random(threadId);
+        final byte[] JSON_INPUT = "\"abc\"".getBytes(StandardCharsets.UTF_8);
+
+        while (System.currentTimeMillis() < endTimeMsecs) {
+            try {
+                // Randomize call order a bit
+                switch (rnd.nextInt() & 3) {
+                case 0:
+                    _testRead(jsonF, JSON_INPUT);
+                    break;
+                case 1:
+                    _testWrite(jsonF);
+                    break;
+                case 2:
+                    _testRead(jsonF, JSON_INPUT);
+                    _testWrite(jsonF);
+                    break;
+                default:
+                    _testWrite(jsonF);
+                    _testRead(jsonF, JSON_INPUT);
+                    break;
+                }
+            } catch (Exception e) {
+                System.err.printf("ERROR: thread %d fail, will exit: (%s) %s\n",
+                        threadId, e.getClass().getName(), e.getMessage());
+                break;
+            }
+            calls.incrementAndGet();
+        }
+    }
+
+    private void _testRead(JsonFactory jsonF, byte[] input) throws Exception
+    {
+        JsonParser p = jsonF.createParser(new ByteArrayInputStream(input));
+        while (p.nextToken() != null) {
+            ;
+        }
+        p.close();
+    }
+
+    private void _testWrite(JsonFactory jsonF) throws Exception
+    {
+        StringWriter w = new StringWriter(16);
+        JsonGenerator g = jsonF.createGenerator(w);
+        g.writeStartArray();
+        g.writeString("foobar");
+        g.writeEndArray();
+        g.close();
+    }
+
+    public static void main(String[] args) throws Exception
+    {
+        RecyclerPoolTest test = new RecyclerPoolTest(THREAD_COUNT);
+        List<String> results = Arrays.asList(
+            test.testPool(JsonFactory.builder()
+                    .recyclerPool(JsonRecyclerPools.newConcurrentDequePool())
+                    .build(),
+                RUNTIME_SECS),
+            test.testPool(JsonFactory.builder()
+                    .recyclerPool(JsonRecyclerPools.newBoundedPool(THREAD_COUNT - 5))
+                    .build(),
+                RUNTIME_SECS),
+            test.testPool(JsonFactory.builder()
+                    .recyclerPool(JsonRecyclerPools.newLockFreePool())
+                    .build(),
+                RUNTIME_SECS)
+        );
+
+        System.out.println("Tests complete! Results:\n");
+        for (String result : results) {
+            System.out.printf(" * %s\n", result);
+        }
+    }
+}