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Replace System.currentTimeMillis() by System.nanoTime() #509

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Replace System.currentTimeMillis() by System.nanoTime() #509

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303adb3
Replace System.currentTimeMillis() by System.nanoTime()
wilderrodrigues Jun 22, 2015
b8d46ff
Add unit tests to cover negative cases
wilderrodrigues Jun 22, 2015
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20 changes: 9 additions & 11 deletions utils/src/com/cloud/utils/Profiler.java
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Original file line number Diff line number Diff line change
Expand Up @@ -23,24 +23,20 @@ public class Profiler {
private Long startTickInMs;
private Long stopTickInMs;

public Profiler() {
startTickInMs = null;
stopTickInMs = null;
}

public long start() {
startTickInMs = System.currentTimeMillis();
startTickInMs = System.nanoTime();
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@DaanHoogland DaanHoogland Jun 23, 2015

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I'd use a new name for the var, like startTickInNanos (and of course stopTickInNanos)

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@wilderrodrigues wilderrodrigues Jun 23, 2015

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The nanoTime() is given in Microseconds. So, the MS still fits in.

Cheers,
Wilder

return startTickInMs.longValue();
}

public long stop() {
stopTickInMs = System.currentTimeMillis();
stopTickInMs = System.nanoTime();
return stopTickInMs.longValue();
}

public long getDuration() {
if (startTickInMs != null && stopTickInMs != null)
if (startTickInMs != null && stopTickInMs != null) {
return stopTickInMs.longValue() - startTickInMs.longValue();
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@DaanHoogland DaanHoogland Jun 23, 2015

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hasn't the semantics changed as it no longer return milliseconds but now micro-(or even nano-) seconds? (this goes for stop and start as well btw. Did you check the callers?

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@wilderrodrigues wilderrodrigues Jun 23, 2015

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I did... and it doesn't change. Only the resolution does,

Quick googled that one here for you: https://blogs.oracle.com/dholmes/entry/inside_the_hotspot_vm_clocks

Implementation is still the same:

image

http://stackoverflow.com/questions/351565/system-currenttimemillis-vs-system-nanotime

Cheers,
Wilder

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@DaanHoogland DaanHoogland Jun 23, 2015

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Yes, and so does the semantics of the return of starts() stop() and getDuration().
I checked; the first two are never cought in a variable but the last one is used in output and to check against settings. There the semantics really changes. It now returns higher numbers then axpected.

}

return -1;
}
Expand All @@ -55,12 +51,14 @@ public boolean isStopped() {

@Override
public String toString() {
if (startTickInMs == null)
if (startTickInMs == null) {
return "Not Started";
}

if (stopTickInMs == null)
if (stopTickInMs == null) {
return "Started but not stopped";
}

return "Done. Duration: " + getDuration() + "ms";
}
}
}
32 changes: 29 additions & 3 deletions utils/test/com/cloud/utils/TestProfiler.java
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Original file line number Diff line number Diff line change
Expand Up @@ -32,11 +32,11 @@ public class TestProfiler extends Log4jEnabledTestCase {
public void testProfiler() {
s_logger.info("testProfiler() started");

Profiler pf = new Profiler();
final Profiler pf = new Profiler();
pf.start();
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
} catch (final InterruptedException e) {
}
pf.stop();

Expand All @@ -46,4 +46,30 @@ public void testProfiler() {

s_logger.info("testProfiler() stopped");
}
}

@Test
public void testProfilerNoStart() {
final Profiler pf = new Profiler();
try {
Thread.sleep(20);
} catch (final InterruptedException e) {
}
pf.stop();

Assert.assertTrue(pf.getDuration() == -1);
Assert.assertFalse(pf.isStarted());
}

@Test
public void testProfilerNoStop() {
final Profiler pf = new Profiler();
pf.start();
try {
Thread.sleep(20);
} catch (final InterruptedException e) {
}

Assert.assertTrue(pf.getDuration() == -1);
Assert.assertFalse(pf.isStopped());
}
}