ADTarm-ehast-experimentalenumforall-pointer-decayjacob/cs343-translationjenkins-sandboxnew-astnew-ast-unique-exprpthread-emulationqualifiedEnum
Last change
on this file since f9bf142 was
be53b87,
checked in by Peter A. Buhr <pabuhr@…>, 5 years ago
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update Java benchmarks with multiple mechanisms to trick the JIT
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-
Property mode set to
100644
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File size:
1.5 KB
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1 | public class JavaThread { |
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2 | // Simplistic low-quality Marsaglia Shift-XOR pseudo-random number generator. |
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3 | // Bijective |
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4 | // Cycle length for non-zero values is 4G-1. |
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5 | // 0 is absorbing and should be avoided -- fixed point. |
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6 | // The returned value is typically masked to produce a positive value. |
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7 | static volatile int Ticket = 0 ; |
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8 | |
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9 | private static int nextRandom (int x) { |
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10 | if (x == 0) { |
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11 | // reseed the PRNG |
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12 | // Ticket is accessed infrequently and does not constitute a coherence hot-spot. |
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13 | // Note that we use a non-atomic racy increment -- the race is rare and benign. |
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14 | // If the race is a concern switch to an AtomicInteger. |
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15 | // In addition accesses to the RW volatile global "Ticket" variable are not |
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16 | // (readily) predictable at compile-time so the JIT will not be able to elide |
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17 | // nextRandom() invocations. |
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18 | x = ++Ticket ; |
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19 | if (x == 0) x = 1 ; |
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20 | } |
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21 | x ^= x << 6; |
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22 | x ^= x >>> 21; |
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23 | x ^= x << 7; |
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24 | return x ; |
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25 | } |
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26 | static int x = 2; |
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27 | |
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28 | static private final int NoOfTimes = Integer.parseInt("1000000") ; |
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29 | |
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30 | public static void helper() { |
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31 | for(int i = 1; i <= NoOfTimes; i += 1) { |
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32 | Thread.yield(); |
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33 | } |
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34 | } |
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35 | public static void InnerMain() { |
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36 | long start = System.nanoTime(); |
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37 | helper(); |
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38 | long end = System.nanoTime(); |
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39 | System.out.println( (end - start) / NoOfTimes ); |
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40 | } |
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41 | public static void main(String[] args) throws InterruptedException { |
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42 | for (int n = Integer.parseInt("5"); --n >= 0 ; ) { |
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43 | InnerMain(); |
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44 | Thread.sleep(2000); // 2 seconds |
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45 | x = nextRandom(x); |
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46 | } |
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47 | if ( x == 0 ) System.out.println(x); |
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48 | } |
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49 | } |
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