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[benchmark] detect iterations overflow

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If for some reason benchmark function is too fast (like when it got
optimized out to nothing), we'd previously hang in infinite loop. Now
we'll catch this condition due to iterations count overflowing.
This commit is contained in:
Aliaksey Kandratsenka 2023-06-21 23:03:33 -04:00
parent e003e91b74
commit ff68bcab60
1 changed files with 10 additions and 2 deletions
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12
benchmark/run_benchmark.c
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@ -27,6 +27,7 @@
#include "run_benchmark.h"
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
@ -80,10 +81,17 @@ static double run_benchmark(struct internal_bench *b)
if (nsec > TRIAL_NSEC) {
break;
}
iterations <<= 1;
iterations = ((unsigned long)iterations) << 1;
if (iterations <= 0) { // overflow
abort();
}
}
while (nsec < TARGET_NSEC) {
iterations = (long)(iterations * TARGET_NSEC * 1.1 / nsec);
double target_iterations = iterations * TARGET_NSEC * 1.1 / nsec;
if (target_iterations > (double)LONG_MAX) {
abort();
}
iterations = target_iterations;
nsec = measure_once(b, iterations);
}
return nsec / iterations;