fixes #67 improves group commit performance test

src/main/java/org/apache/accumulo/testing/performance/tests/GroupCommitPT.java

@@ -17,7 +17,6 @@
 
 package org.apache.accumulo.testing.performance.tests;
 
-import java.text.DecimalFormat;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.Map;
@@ -37,8 +36,13 @@
 import org.apache.accumulo.testing.performance.Report;
 import org.apache.accumulo.testing.performance.SystemConfiguration;
 
+import com.google.common.base.Preconditions;
+
 public class GroupCommitPT implements PerformanceTest {
 
+  private static final int NUM_MUTATIONS = 2048 * 1024;
+  private static final int NUM_FLUSHES = 1024;
+
   static Mutation createRandomMutation(Random rand) {
     byte row[] = new byte[16];
 
@@ -60,37 +64,34 @@ static Mutation createRandomMutation(Random rand) {
 
   static class WriteTask implements Runnable {
 
-    private int numToWrite;
-    private int numToBatch;
+    private int batchSize;
     private BatchWriter bw;
-    private volatile long time = -1;
+    private volatile int written = 0;
 
-    WriteTask(BatchWriter bw, int numToWrite, int numToBatch) throws Exception {
+    WriteTask(BatchWriter bw, int numMutations) throws Exception {
+      Preconditions.checkArgument(numMutations >= NUM_FLUSHES);
+      Preconditions.checkArgument(numMutations % NUM_FLUSHES == 0);
       this.bw = bw;
-      this.numToWrite = numToWrite;
-      this.numToBatch = numToBatch;
+      this.batchSize = numMutations / NUM_FLUSHES;
     }
 
     @Override
     public void run() {
       Random rand = new Random();
 
+      int written = 0;
+
       try {
-        long t1 = System.currentTimeMillis();
-        for (int i = 0; i < numToWrite; i++) {
+        for (int i = 0; i < NUM_FLUSHES; i++) {
           Mutation mut = createRandomMutation(rand);
 
-          for (int j = 0; j < numToBatch; j++) {
+          for (int j = 0; j < batchSize; j++) {
             bw.addMutation(mut);
+            written++;
           }
 
           bw.flush();
         }
-
-        // bw.flush();
-
-        long t2 = System.currentTimeMillis();
-        this.time = t2 - t1;
       } catch (Exception e) {
         e.printStackTrace();
       } finally {
@@ -101,10 +102,12 @@ public void run() {
         }
 
       }
+
+      this.written = written;
     }
 
-    long getTime() {
-      return time;
+    public int getWritten() {
+      return written;
     }
   }
 
@@ -121,43 +124,50 @@ public SystemConfiguration getSystemConfig() {
 
   @Override
   public Report runTest(Environment env) throws Exception {
-    int numThreads = 128;
 
     Report.Builder report = Report.builder();
     report.id("mutslam");
-    report.description("Runs multiple threads to test performance of a group commit. "
-        + " This tests threads with client side group commit, using a single batch writer");
-
-    double batchValues;
-
-    for (int i = 0; i < 6; i++) {
-      // This test threads w/ group commit on the client side, using a single batch writer.
-      // Each thread flushes after each mutation.
-      batchValues = runBatch(env, numThreads, 1);
-
-      report.info("threadsTime" + i, new Double(new DecimalFormat("#0.00").format(batchValues)),
-          "Time it took the task to run in milliseconds");
-      report.info("threads" + i, i, "Number of threads");
-      report.info("batch" + i, 1, "Number of batches");
+    report.description("Data written to Accumulo is appended to a write ahead log before its made "
+        + "available for scan.  There is a single write ahead log per tablet server.  Data from "
+        + "multiple concurrent clients is batched together and appended to the write ahead log, "
+        + "this is called group commit.  If group commit is not working properly, then performance"
+        + " of concurrent writes could suffer.  This performance test measures group commit.  In "
+        + "an Accumulo client, when the batch writer is flushed this forces an append to the write"
+        + " ahead log.  The batch writer flush call does not return until the append is complete. "
+        + "This test writes the same amount of data using different numbers of threads to check if"
+        + " group commit is working properly.  When the test is using one thread it will write "
+        + "2048K total mutations calling flush on the batchwriter 1024 times.  When"
+        + " the test is running two threads, each thread will write 1024K mutations calling "
+        + "flush 1024 times.  The pattern is that as the number of threads increases"
+        + ", the amount of data written per thread decreases proportionally.  However the number of"
+        + " flushes done by threads is constant.  If group commit is working well, then the overall"
+        + " write rate should not be significantly less as the number of threads increases.");
+
+    report.parameter("num_mutations", NUM_MUTATIONS,
+        "The total number of mutations each test will write.  Each thread in a test will write num_mutations/num_threads_in_test mutations.");
+    report.parameter("num_flushes", NUM_FLUSHES,
+        "The number of times each thread will flush its batch writer.  The flushes are spread evenly between mutations.");
+
+    // number of threads to run for each test
+    int tests[] = new int[] {1, 2, 4, 8, 16, 32, 64};
+
+    // run warm up test
+    for (int numThreads : tests) {
+      runTest(report, env, numThreads, true);
     }
 
-    for (int i = 0; i < 6; i++) {
-      // This tests a single thread writing a different batch sizes of mutations,
-      // flushing after each batch. Group commit should approach these times for the same number
-      // mutations.
-
-      batchValues = runBatch(env, 1, numThreads);
-
-      report.info("batchTime" + i, new Double(new DecimalFormat("#0.00").format(batchValues)),
-          "Time it took the task to run in milliseconds");
-      report.info("threads" + i, i, "Number of threads");
-      report.info("batch" + i, 1, "Number of batches");
+    // run real test
+    for (int numThreads : tests) {
+      runTest(report, env, numThreads, false);
     }
 
     return report.build();
   }
 
-  private double runBatch(Environment env, int numThreads, int numToBatch) throws Exception {
+  private void runTest(Report.Builder report, Environment env, int numThreads, boolean warmup)
+      throws Exception {
+
+    Preconditions.checkArgument(NUM_MUTATIONS % numThreads == 0);
 
     String tableName = "mutslam";
     env.getClient().tableOperations().create(tableName);
@@ -168,21 +178,22 @@ private double runBatch(Environment env, int numThreads, int numToBatch) throws
       entry.getValue();
     }
 
-    // number of batches each thread should write
-    int numToWrite = 100;
+    int mutationsPerThread = NUM_MUTATIONS / numThreads;
 
     ArrayList<WriteTask> wasks = new ArrayList<WriteTask>();
     ArrayList<Thread> threads = new ArrayList<Thread>();
 
     for (int i = 0; i < numThreads; i++) {
       WriteTask wask = new WriteTask(env.getClient().createBatchWriter(tableName,
-          new BatchWriterConfig().setMaxWriteThreads(1)), numToWrite, numToBatch);
+          new BatchWriterConfig().setMaxWriteThreads(1)), mutationsPerThread);
 
       wasks.add(wask);
       Thread thread = new Thread(wask);
       threads.add(thread);
     }
 
+    long t1 = System.currentTimeMillis();
+
     for (Thread thread : threads) {
       thread.start();
     }
@@ -191,19 +202,19 @@ private double runBatch(Environment env, int numThreads, int numToBatch) throws
       thread.join();
     }
 
-    long sum = 0;
-    for (WriteTask writeTask : wasks) {
-      sum += writeTask.getTime();
-    }
+    long t2 = System.currentTimeMillis();
 
-    // System.out.printf(
-    // "\ttime: %8.2f #threads: %3d #batch: %2d #mutations: %4d rate: %6.2f mutations/ms\n",
-    // sum / (double) wasks.size(), numThreads, numToBatch, totalNumMutations,
-    // totalNumMutations / (sum / (double) wasks.size()));
+    // ensure all thread wrote the expected number of mutations
+    Preconditions.checkState(wasks.stream().mapToInt(WriteTask::getWritten).sum() == NUM_MUTATIONS);
 
     env.getClient().tableOperations().delete(tableName);
-
-    return sum / (double) wasks.size(); // time
+    if (warmup) {
+      report.info("warmup_rate_" + numThreads, NUM_MUTATIONS, t2 - t1, "The warmup rate at which "
+          + numThreads + " threads wrote data. The rate is mutations per second.");
+    } else {
+      report.result("rate_" + numThreads, NUM_MUTATIONS, t2 - t1, "The rate at which " + numThreads
+          + " threads wrote data. The rate is mutations per second.");
+    }
   }
 
 }