Output p99 latency on each line

src/main/java/com/yugabyte/sample/common/metrics/Metric.java

@@ -25,7 +25,7 @@ public Metric(String name) {
   }
 
   public synchronized void observe(Observation o) {
-    readableStatsMetric.accumulate(o.getCount(), o.getLatencyNanos());
+    readableStatsMetric.observe(o);
     jsonStatsMetric.observe(o);
   }
 

src/main/java/com/yugabyte/sample/common/metrics/ReadableStatsMetric.java

@@ -16,41 +16,49 @@
 import org.apache.log4j.Logger;
 
 public class ReadableStatsMetric {
-    private static final Logger LOG = Logger.getLogger(ReadableStatsMetric.class);
-    String name;
-    private final Object lock = new Object();
-    protected long curOpCount = 0;
-    protected long curOpLatencyNanos = 0;
-    protected long totalOpCount = 0;
-    private long lastSnapshotNanos;
+  private static final Logger LOG = Logger.getLogger(ReadableStatsMetric.class);
+  String name;
+  private final Object lock = new Object();
+  protected long curOpCount = 0;
+  protected long curOpLatencyNanos = 0;
+  protected long totalOpCount = 0;
+  private long lastSnapshotNanos;
+  private StatsTracker quantileStats;
 
-    public ReadableStatsMetric(String name) {
-        this.name = name;
-        lastSnapshotNanos = System.nanoTime();
-    }
+  public ReadableStatsMetric(String name) {
+    this.name = name;
+    lastSnapshotNanos = System.nanoTime();
+    quantileStats = new StatsTracker();
+  }
 
-    /**
-     * Accumulate metrics with operations processed as one batch.
-     * @param numOps number of ops processed as one batch
-     * @param batchLatencyNanos whole batch latency
-     */
-    public synchronized void accumulate(long numOps, long batchLatencyNanos) {
-        curOpCount += numOps;
-        curOpLatencyNanos += batchLatencyNanos * numOps;
-        totalOpCount += numOps;
-    }
+  public synchronized void observe(Observation o) {
+    accumulate(o.getCount(), o.getLatencyNanos());
+    quantileStats.observe(o.getLatencyMillis());
+  }
 
-    public synchronized String getMetricsAndReset() {
-        long currNanos = System.nanoTime();
-        long elapsedNanos = currNanos - lastSnapshotNanos;
-        LOG.debug("currentOpLatency: " + curOpLatencyNanos + ", currentOpCount: " + curOpCount);
-        double ops_per_sec =
-                (elapsedNanos == 0) ? 0 : (curOpCount * 1000000000 * 1.0 / elapsedNanos);
-        double latency = (curOpCount == 0) ? 0 : (curOpLatencyNanos / 1000000 * 1.0 / curOpCount);
-        curOpCount = 0;
-        curOpLatencyNanos = 0;
-        lastSnapshotNanos = currNanos;
-        return String.format("%s: %.2f ops/sec (%.2f ms/op), %d total ops",
-                name, ops_per_sec, latency, totalOpCount);
-    }
+  /**
+   * Accumulate metrics with operations processed as one batch.
+   *
+   * @param numOps number of ops processed as one batch
+   * @param batchLatencyNanos whole batch latency
+   */
+  public synchronized void accumulate(long numOps, long batchLatencyNanos) {
+    curOpCount += numOps;
+    curOpLatencyNanos += batchLatencyNanos * numOps;
+    totalOpCount += numOps;
+  }
+
+  public synchronized String getMetricsAndReset() {
+    long currNanos = System.nanoTime();
+    long elapsedNanos = currNanos - lastSnapshotNanos;
+    LOG.debug("currentOpLatency: " + curOpLatencyNanos + ", currentOpCount: " + curOpCount);
+    double ops_per_sec = (elapsedNanos == 0) ? 0 : (curOpCount * 1000000000 * 1.0 / elapsedNanos);
+    double latency = (curOpCount == 0) ? 0 : (curOpLatencyNanos / 1000000 * 1.0 / curOpCount);
+    curOpCount = 0;
+    curOpLatencyNanos = 0;
+    lastSnapshotNanos = currNanos;
+    return String.format(
+        "%s: %.2f ops/sec (%.2f ms/op, %.2f ms p99), %d total ops",
+        name, ops_per_sec, latency, quantileStats.stats.getPercentile(99), totalOpCount);
+  }
 }

src/main/java/com/yugabyte/sample/common/metrics/StatsTracker.java

@@ -4,24 +4,24 @@
 import org.apache.commons.math3.stat.descriptive.DescriptiveStatistics;
 
 public class StatsTracker {
-    private DescriptiveStatistics stats;
+  public DescriptiveStatistics stats;
 
-    public StatsTracker() {
-        this.stats = new DescriptiveStatistics();
-    }
+  public StatsTracker() {
+    this.stats = new DescriptiveStatistics();
+  }
 
-    public synchronized void observe(double value) {
-        stats.addValue(value);
-    }
+  public synchronized void observe(double value) {
+    stats.addValue(value);
+  }
 
-    public synchronized JsonObject getJson() {
-        JsonObject json = new JsonObject();
-        json.addProperty("mean", stats.getMean());
-        json.addProperty("variance", stats.getVariance());
-        json.addProperty("sampleSize", stats.getN());
-        json.addProperty("min", stats.getMin());
-        json.addProperty("max", stats.getMax());
-        json.addProperty("p99", stats.getPercentile(99));
-        return json;
-    }
+  public synchronized JsonObject getJson() {
+    JsonObject json = new JsonObject();
+    json.addProperty("mean", stats.getMean());
+    json.addProperty("variance", stats.getVariance());
+    json.addProperty("sampleSize", stats.getN());
+    json.addProperty("min", stats.getMin());
+    json.addProperty("max", stats.getMax());
+    json.addProperty("p99", stats.getPercentile(99));
+    return json;
+  }
 }