Occasionally I see thread execution hiccups on my Motorola Droid
(currently running 2.1 but I saw it with 2.0.1, too). Normally my
dummy thread (full tilt, foreground, not doing *anything* else) runs
in about 5-6mS. However, I see a second hump around 13-14mS and
stragglers anywhere out to 80mS (typically around 35mS, though).
What is going on? Why is this scheduling so non-deterministically?
What is the solution?
I could deal with a couple mS slower if it would get rid of those
stragglers that exist the whole way out to 50-80mS.
Thanks.
If I run a single thread full tilt, I see execution times like the
following (milliseconds:number of times seen):
04-09 00:40:06.450: VERBOSE/*****(7177): Run ended ... dumping...
04-09 00:40:06.450: VERBOSE/CalcDelta:(7177): 5: 3915
04-09 00:40:06.457: VERBOSE/CalcDelta:(7177): 6: 6221
04-09 00:40:06.457: VERBOSE/CalcDelta:(7177): 7: 63
04-09 00:40:06.465: VERBOSE/CalcDelta:(7177): 8: 47
04-09 00:40:06.465: VERBOSE/CalcDelta:(7177): 9: 4
04-09 00:40:06.473: VERBOSE/CalcDelta:(7177): 10: 9
04-09 00:40:06.473: VERBOSE/CalcDelta:(7177): 11: 7
04-09 00:40:06.481: VERBOSE/CalcDelta:(7177): 12: 7
04-09 00:40:06.489: VERBOSE/CalcDelta:(7177): 13: 22
04-09 00:40:06.489: VERBOSE/CalcDelta:(7177): 14: 26
04-09 00:40:06.496: VERBOSE/CalcDelta:(7177): 15: 8
04-09 00:40:06.496: VERBOSE/CalcDelta:(7177): 16: 7
04-09 00:40:06.504: VERBOSE/CalcDelta:(7177): 17: 4
04-09 00:40:06.504: VERBOSE/CalcDelta:(7177): 18: 3
04-09 00:40:06.512: VERBOSE/CalcDelta:(7177): 19: 5
04-09 00:40:06.512: VERBOSE/CalcDelta:(7177): 21: 11
04-09 00:40:06.520: VERBOSE/CalcDelta:(7177): 22: 1
04-09 00:40:06.520: VERBOSE/CalcDelta:(7177): 23: 2
04-09 00:40:06.528: VERBOSE/CalcDelta:(7177): 25: 1
04-09 00:40:06.528: VERBOSE/CalcDelta:(7177): 26: 1
04-09 00:40:06.536: VERBOSE/CalcDelta:(7177): 27: 1
04-09 00:40:06.536: VERBOSE/CalcDelta:(7177): 29: 4
04-09 00:40:06.543: VERBOSE/CalcDelta:(7177): 30: 1
04-09 00:40:06.543: VERBOSE/CalcDelta:(7177): 36: 1
04-09 00:40:06.551: VERBOSE/CalcDelta:(7177): 37: 1
04-09 00:40:06.551: VERBOSE/CalcDelta:(7177): 40: 1
04-09 00:40:06.559: VERBOSE/CalcDelta:(7177): 45: 2
04-09 00:40:06.559: VERBOSE/CalcDelta:(7177): 47: 1
04-09 00:40:06.567: VERBOSE/CalcDelta:(7177): 53: 1
<code>
import java.util.Random;
import android.app.Activity;
import android.os.Bundle;
import android.os.SystemClock;
import android.util.Log;
public class Run extends Activity {
private long entryMillis = SystemClock.uptimeMillis();
private long exitMillis = SystemClock.uptimeMillis();
private long startMillis = SystemClock.uptimeMillis();
long calcDeltaMillis[] = new long[1000];
long funcDeltaMillis[] = new long[1000];
long randomTime = 0;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
@Override
protected void onResume() {
super.onResume();
Thread t = new Thread() {
public void run() {
doTimingThread();
}
};
t.start();
}
void doTimingThread() {
Random rg = new Random();
Log.v("*****", "Entering timing thread...");
startMillis = SystemClock.uptimeMillis();
while(true) {
entryMillis = SystemClock.uptimeMillis();
for(int ii=0; ii<4000; ++ii) {
randomTime += rg.nextInt();
}
exitMillis = SystemClock.uptimeMillis();
calcDeltaMillis[(int)(exitMillis-entryMillis)] += 1;
if (SystemClock.uptimeMillis() >= startMillis + 60000) {
dumpAndEraseTables();
startMillis = SystemClock.uptimeMillis();
}
}
}
public void dumpAndEraseTables() {
Log.v("*****", "Run ended ... dumping...");
for(int ii=0; ii<1000; ++ii) {
if (calcDeltaMillis[ii] != 0) {
Log.v("CalcDelta:", String.format("%3d: %d", ii,
calcDeltaMillis[ii]));
calcDeltaMillis[ii] = 0;
}
}
}
@Override
protected void onPause() {
super.onPause();
}
}
</code>
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