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spectrum-scanner: Run time performance improvements #52
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jnohlgard
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This change does truncate the averaged ED to integers, but I don't think the precision matters here because radio noise is not exact, we are only interested in seeing which channels are occupied. |
smlng
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Oct 17, 2018
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Looks good code-wise, but also the output changed considerably: i.e. the values are more wide-spread. On master its mostly blue-ish but with this PR it get yellow and green, too. Which I think is good because it makes differences more visible.
Btw. I tested with samr21-xpro, everything still works - with these IMHO good visual enhancements.
jnohlgard
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Oct 17, 2018
spectrum-scanner/main.c
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| @@ -125,10 +126,10 @@ void spectrum_scanner(unsigned long interval_us) | |||
| print("] ", 2); | |||
| for (unsigned int ch = IEEE802154_CHANNEL_MIN; ch <= IEEE802154_CHANNEL_MAX; ++ch) { | |||
| /* Compute the average pseudo-energy and convert back to dB */ | |||
| ed_average[k][ch] = logf(ed_average[k][ch] / count) * 128.f; | |||
| uint32_t ed = ilogbf(ed_average[k][ch] / count); | |||
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This should be int32_t
jnohlgard
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Experiments show that using ldexpf, ilogbf yields significantly faster run time performance on Cortex-M0+ without floating point hardware.
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Experiments show that using ldexpf, ilogbf yields significantly faster
run time performance on Cortex-M0+ without floating point hardware.