| 1 |
import java.util.concurrent.*; |
| 2 |
import java.util.Random; |
| 3 |
|
| 4 |
public class TimeUnitLoops { |
| 5 |
|
| 6 |
static final LoopHelpers.SimpleRandom rng = new LoopHelpers.SimpleRandom(); |
| 7 |
|
| 8 |
/** |
| 9 |
* False value allows aggressive inlining of cvt() calls from |
| 10 |
* test(). True value prevents any inlining, requiring virtual |
| 11 |
* method dispatch. |
| 12 |
*/ |
| 13 |
static final boolean PREVENT_INLINING = true; |
| 14 |
|
| 15 |
// The following all are used by inlining prevention clause: |
| 16 |
static int index = 0; |
| 17 |
static final int NUNITS = 100; |
| 18 |
static final TimeUnit[] units = new TimeUnit[NUNITS]; |
| 19 |
static { |
| 20 |
TimeUnit[] v = TimeUnit.values(); |
| 21 |
for (int i = 0; i < NUNITS; ++i) |
| 22 |
units[i] = v[rng.next() % v.length]; |
| 23 |
} |
| 24 |
|
| 25 |
public static void main(String[] args) throws Exception { |
| 26 |
long start = System.currentTimeMillis(); |
| 27 |
long s = 0; |
| 28 |
for (int i = 0; i < 100; ++i) { |
| 29 |
s += test(); |
| 30 |
if (s == start) System.out.println(" "); |
| 31 |
} |
| 32 |
long end = System.currentTimeMillis(); |
| 33 |
System.out.println("Time: " + (end - start) + " ms"); |
| 34 |
} |
| 35 |
|
| 36 |
static long test() { |
| 37 |
long sum = 0; |
| 38 |
int x = rng.next(); |
| 39 |
for (int i = 0; i < 1000000; ++i) { |
| 40 |
long l = (long)x + (long)x; |
| 41 |
sum += cvt(l, TimeUnit.SECONDS); |
| 42 |
sum += TimeUnit.MILLISECONDS.toMicros(l+2); |
| 43 |
sum += cvt(l+17, TimeUnit.NANOSECONDS); |
| 44 |
sum += cvt(l+42, TimeUnit.MILLISECONDS); |
| 45 |
x = LoopHelpers.compute4(x); |
| 46 |
} |
| 47 |
return sum + x; |
| 48 |
} |
| 49 |
|
| 50 |
static long cvt(long d, TimeUnit u) { |
| 51 |
if (PREVENT_INLINING) { |
| 52 |
u = units[index]; |
| 53 |
index = (index+1) % NUNITS; |
| 54 |
} |
| 55 |
|
| 56 |
return u.toNanos(d); |
| 57 |
} |
| 58 |
} |
