--- jsr166/src/test/loops/MapLoops.java 2005/05/02 19:19:38 1.1 +++ jsr166/src/test/loops/MapLoops.java 2015/09/12 19:36:34 1.12 @@ -1,28 +1,18 @@ -/* - * @test - * @synopsis Exercise multithreaded maps, by default - * ConcurrentHashMap. Each thread does a random walk though elements - * of "key" array. On each iteration, it checks if table includes key. - * If absent, with probablility pinsert it inserts it, and if present, - * with probablility premove it removes it. (pinsert and premove are - * expressed as percentages to simplify parsing from command line.) - */ /* * Written by Doug Lea with assistance from members of JCP JSR-166 - * Expert Group and released to the public domain. Use, modify, and - * redistribute this code in any way without acknowledgement. + * Expert Group and released to the public domain, as explained at + * http://creativecommons.org/publicdomain/zero/1.0/ */ - import java.util.*; import java.util.concurrent.*; public class MapLoops { - static int nkeys = 10000; + static int nkeys = 1000; static int pinsert = 60; static int premove = 2; static int maxThreads = 100; - static int nops = 8000000; + static int nops = 1000000; static int removesPerMaxRandom; static int insertsPerMaxRandom; @@ -30,36 +20,39 @@ public class MapLoops { public static void main(String[] args) throws Exception { - Class mapClass = null; + Class mapClass = null; if (args.length > 0) { try { mapClass = Class.forName(args[0]); - } catch(ClassNotFoundException e) { + } catch (ClassNotFoundException e) { throw new RuntimeException("Class " + args[0] + " not found."); } } - else + else mapClass = java.util.concurrent.ConcurrentHashMap.class; - if (args.length > 1) + if (args.length > 1) maxThreads = Integer.parseInt(args[1]); - if (args.length > 2) + if (args.length > 2) nkeys = Integer.parseInt(args[2]); - if (args.length > 3) + if (args.length > 3) pinsert = Integer.parseInt(args[3]); - if (args.length > 4) + if (args.length > 4) premove = Integer.parseInt(args[4]); - if (args.length > 5) + if (args.length > 5) nops = Integer.parseInt(args[5]); + if (nops < nkeys) + nops = nkeys; + // normalize probabilities wrt random number generator removesPerMaxRandom = (int)(((double)premove/100.0 * 0x7FFFFFFFL)); insertsPerMaxRandom = (int)(((double)pinsert/100.0 * 0x7FFFFFFFL)); - + System.out.print("Class: " + mapClass.getName()); System.out.print(" threads: " + maxThreads); System.out.print(" size: " + nkeys); @@ -68,23 +61,25 @@ public class MapLoops { System.out.print(" ops: " + nops); System.out.println(); - int k = 1; int warmups = 2; - for (int i = 1; i <= maxThreads;) { - Thread.sleep(100); - test(i, nkeys, mapClass); - if (warmups > 0) - --warmups; - else if (i == k) { - k = i << 1; - i = i + (i >>> 1); - } - else if (i == 1 && k == 2) { - i = k; - warmups = 1; + for (int reps = 0; reps < 3; ++reps) { + int k = 1; + for (int i = 1; i <= maxThreads;) { + Thread.sleep(100); + test(i, nkeys, mapClass); + if (warmups > 0) + --warmups; + else if (i == k) { + k = i << 1; + i = i + (i >>> 1); + } + else if (i == 1 && k == 2) { + i = k; + warmups = 1; + } + else + i = k; } - else - i = k; } pool.shutdown(); } @@ -92,7 +87,7 @@ public class MapLoops { static Integer[] makeKeys(int n) { LoopHelpers.SimpleRandom rng = new LoopHelpers.SimpleRandom(); Integer[] key = new Integer[n]; - for (int i = 0; i < key.length; ++i) + for (int i = 0; i < key.length; ++i) key[i] = new Integer(rng.next()); return key; } @@ -107,23 +102,24 @@ public class MapLoops { } } - static void test(int i, int nkeys, Class mapClass) throws Exception { + static void test(int i, int nkeys, Class mapClass) throws Exception { System.out.print("Threads: " + i + "\t:"); Map map = (Map)mapClass.newInstance(); Integer[] key = makeKeys(nkeys); // Uncomment to start with a non-empty table // for (int j = 0; j < nkeys; j += 4) // start 1/4 occupied // map.put(key[j], key[j]); + shuffleKeys(key); LoopHelpers.BarrierTimer timer = new LoopHelpers.BarrierTimer(); CyclicBarrier barrier = new CyclicBarrier(i+1, timer); - for (int t = 0; t < i; ++t) - pool.execute(new Runner(map, key, barrier)); + for (int t = 0; t < i; ++t) + pool.execute(new Runner(t, map, key, barrier)); barrier.await(); barrier.await(); long time = timer.getTime(); - long tpo = time / (i * (long)nops); + long tpo = time / (i * (long) nops); System.out.print(LoopHelpers.rightJustify(tpo) + " ns per op"); - double secs = (double)(time) / 1000000000.0; + double secs = (double) time / 1000000000.0; System.out.println("\t " + secs + "s run time"); map.clear(); } @@ -131,30 +127,32 @@ public class MapLoops { static class Runner implements Runnable { final Map map; final Integer[] key; - final LoopHelpers.SimpleRandom rng = new LoopHelpers.SimpleRandom(); + final LoopHelpers.SimpleRandom rng; final CyclicBarrier barrier; int position; int total; - Runner(Map map, Integer[] key, CyclicBarrier barrier) { - this.map = map; - this.key = key; + Runner(int id, Map map, Integer[] key, CyclicBarrier barrier) { + this.map = map; + this.key = key; this.barrier = barrier; position = key.length / 2; + rng = new LoopHelpers.SimpleRandom((id + 1) * 8862213513L); + rng.next(); } int step() { - // random-walk around key positions, bunching accesses + // random-walk around key positions, bunching accesses int r = rng.next(); position += (r & 7) - 3; - while (position >= key.length) position -= key.length; + while (position >= key.length) position -= key.length; while (position < 0) position += key.length; Integer k = key[position]; Integer x = map.get(k); if (x != null) { - if (x.intValue() != k.intValue()) + if (x.intValue() != k.intValue()) throw new Error("bad mapping: " + x + " to " + k); if (r < removesPerMaxRandom) { @@ -166,9 +164,9 @@ public class MapLoops { } else if (r < insertsPerMaxRandom) { ++position; - map.put(k, k); + map.putIfAbsent(k, k); return 2; - } + } // Uncomment to add a little computation between accesses // total += LoopHelpers.compute1(k.intValue()); @@ -180,7 +178,7 @@ public class MapLoops { try { barrier.await(); int ops = nops; - while (ops > 0) + while (ops > 0) ops -= step(); barrier.await(); } @@ -190,4 +188,3 @@ public class MapLoops { } } } -