Function testSpeed

samples/Basic_ProgMem/app/TestProgmem.cpp:164–220

* Run a load of iterations for PSTR/FSTR options to illustrate relative performance. */

 * Run a load of iterations for PSTR/FSTR options to illustrate relative performance.
 */
void testSpeed(Print& out)
{
	const unsigned iterations = 200;

	out.printf("Speed tests, %u iterations, times in microseconds\n", iterations);
	ElapseTimer timer;
	uint32_t baseline, elapsed;

	_FPUTS("Baseline test, read string in RAM...");
	unsigned sum = 0;
	timer.start();
	for(unsigned i = 0; i < iterations; ++i) {
		sum += sumBuffer(demoText, sizeof(demoText));
	}
	baseline = timer.elapsedTime();
	out << "Elapsed: " << baseline << ", sum " << sum << endl;

#define END()                                                                                                          \
	elapsed = timer.elapsedTime();                                                                                     \
	out << "Elapsed: " << elapsed << " (baseline + " << elapsed - baseline << "), sum " << sum << endl;

	_FPUTS("Load PSTR into stack buffer...");
	sum = 0;
	timer.start();
	for(unsigned i = 0; i < iterations; ++i) {
		LOAD_PSTR(buf, demoPSTR1);
		sum += sumBuffer(buf, sizeof(buf));
	}
	END()

	_FPUTS("Load PSTR into String...");
	sum = 0;
	timer.start();
	for(unsigned i = 0; i < iterations; ++i) {
		String s(demoFSTR1.data());
		sum += sumBuffer(s.c_str(), s.length() + 1);
	}
	END()

	_FPUTS("Load FlashString into stack buffer...");
	sum = 0;
	timer.start();
	for(unsigned i = 0; i < iterations; ++i) {
		LOAD_FSTR(buf, demoFSTR1);
		sum += sumBuffer(buf, sizeof(buf));
	}
	END()

	_FPUTS("Load FlashString into String...");
	sum = 0;
	timer.start();
	for(unsigned i = 0; i < iterations; ++i) {
		String s(demoFSTR1);
		sum += sumBuffer(s.c_str(), s.length() + 1);
	}
	END()
}