New Chronicle-Map

src/test/java/net/openhft/chronicle/map/Histogram.java

@@ -0,0 +1,84 @@
+/*
+ * Copyright 2014 Higher Frequency Trading http://www.higherfrequencytrading.com
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.openhft.chronicle.map;
+
+/**
+ * Created by peter on 28/02/14.
+ */
+public class Histogram {
+    static final String[] FRACTION_STR = "worst,99.99,99.9,99,90,50".split(",");
+    static final int[] FRACTIONS = {Integer.MAX_VALUE, 10000, 1000, 100, 10, 2};
+    static final int BITS_OF_ACCURACY = 5;
+    final int[] counters = new int[40 << BITS_OF_ACCURACY];
+    static final int MANTISSA = 52;
+    static final int BITS_TO_TRUNCATE = MANTISSA - BITS_OF_ACCURACY;
+    long count = 0;
+
+    public void sample(long value) {
+        long rawValue = Double.doubleToRawLongBits(value) >> BITS_TO_TRUNCATE;
+        int bucket = (int) rawValue - (1023 << BITS_OF_ACCURACY);
+        counters[bucket]++;
+        count++;
+    }
+
+    public void printResults() {
+        for (int i = 0; i < counters.length; i++) {
+            if (counters[i] == 0) continue;
+            double d = indexToDouble(i);
+            if (d < 10000 && d * counters[i] < 20000) continue;
+            System.out.println((long) d + ":" + counters[i]);
+        }
+    }
+
+    private double indexToDouble(int i) {
+        return Double.longBitsToDouble((i + (1023L << BITS_OF_ACCURACY)) << BITS_TO_TRUNCATE);
+    }
+
+    public void printPercentiles() {
+        printPercentiles("");
+    }
+
+    public void printPercentiles(String tail) {
+        long[] times = new long[FRACTIONS.length];
+        int f = 0;
+        long total = 0;
+        for (int pos = counters.length - 1; pos >= 0 && f < FRACTIONS.length; pos--) {
+            total += counters[pos];
+            if (total > count / FRACTIONS[f]) {
+                times[f++] = (long) indexToDouble(pos);
+            }
+        }
+        // print in reverse order.
+        StringBuilder sb = new StringBuilder();
+        for (int i = FRACTIONS.length - 1; i >= 0; i--) {
+            sb.append(FRACTION_STR[i]).append("/");
+        }
+        sb.setLength(sb.length() - 1);
+        sb.append(" : ");
+        for (int i = FRACTIONS.length - 1; i >= 0; i--) {
+            long time = times[i];
+            if (time < 10000)
+                sb.append(time / 100 / 10.0);
+            else
+                sb.append(time / 1000);
+            sb.append(" / ");
+        }
+        sb.setLength(sb.length() - 3);
+        sb.append(tail);
+        System.out.println(sb);
+    }
+}