Column: Embedded design
We compile and run the application with these changes, without using the “fl oat_ abi=hard” compiler option and generate trace data. We can then view the trace data in Tracealyzer, confi gure a custom interval, open the Interval Timeline view and see the resulting information in Figure 7. We see that while for the most part the
Figure 4: The graph of another trace But wait, there’s more: we can also
visualise the amount of time each sine calculation takes in Tracealyzer by using Custom Intervals. To do this, we remove the invocation of tracef with the computed sine values and insert tracing of “Start” and “Stop” user events (similar to what was done in a previous article):
for (t = 0; t < 1000; t++) {
tracef(“Start”); sample = sin((2*M_PI*freq*t)/sample_ freq); tracef(“Stop”); }
execution of the function takes on the order of tens of microseconds, there are a few outliers. We see that in one case, the function took approximately 200 microseconds to execute and, in another case, it took about 1.05 milliseconds! If we do the same aſt er adding the
hard ABI option (but not the NEON extensions), we see Interval Timeline view as per Figure 8. Again, we see similar behaviour as with the soſt ABI. While most of the executions took tens of microseconds, there are a few outliers in the range 100-200 microseconds. We also see an invocation that almost took 1.1 milliseconds!
Figure 5: Process suspension 10 June 2021
www.electronicsworld.co.uk
Figure 6: Sine wave process suspension
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46
