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/* |
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* Written by Doug Lea with assistance from members of JCP JSR-166 |
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* Expert Group and released to the public domain, as explained at |
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* http://creativecommons.org/publicdomain/zero/1.0/ |
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*/ |
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import java.util.concurrent.*; |
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import java.util.Random; |
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|
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public class TimeUnitLoops { |
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|
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static final LoopHelpers.SimpleRandom rng = new LoopHelpers.SimpleRandom(); |
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|
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/** |
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* False value allows aggressive inlining of cvt() calls from |
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* test(). True value prevents any inlining, requiring virtual |
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* method dispatch. |
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*/ |
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static final boolean PREVENT_INLINING = true; |
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|
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// The following all are used by inlining prevention clause: |
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static int index = 0; |
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static final int NUNITS = 100; |
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static final TimeUnit[] units = new TimeUnit[NUNITS]; |
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static { |
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TimeUnit[] v = TimeUnit.values(); |
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for (int i = 0; i < NUNITS; ++i) |
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units[i] = v[rng.next() % v.length]; |
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} |
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|
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public static void main(String[] args) throws Exception { |
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long start = System.currentTimeMillis(); |
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long s = 0; |
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for (int i = 0; i < 100; ++i) { |
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s += test(); |
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if (s == start) System.out.println(" "); |
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} |
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long end = System.currentTimeMillis(); |
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System.out.println("Time: " + (end - start) + " ms"); |
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} |
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|
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static long test() { |
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long sum = 0; |
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int x = rng.next(); |
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for (int i = 0; i < 1000000; ++i) { |
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long l = (long) x + (long) x; |
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sum += cvt(l, TimeUnit.SECONDS); |
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sum += TimeUnit.MILLISECONDS.toMicros(l+2); |
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sum += cvt(l+17, TimeUnit.NANOSECONDS); |
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sum += cvt(l+42, TimeUnit.MILLISECONDS); |
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x = LoopHelpers.compute4(x); |
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} |
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return sum + x; |
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} |
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|
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static long cvt(long d, TimeUnit u) { |
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if (PREVENT_INLINING) { |
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u = units[index]; |
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index = (index+1) % NUNITS; |
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} |
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|
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return u.toNanos(d); |
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} |
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} |
