Fix dividing 0 error in stress/cpp/microbench

Summary:
Per issue #2356, some CXX compilers may optimize away the
new/delete operation in stress/cpp/microbench.cpp.
Thus, this commit (1) bumps the time interval to 1 if it is 0, and
(2) modifies the pointers in the microbench to volatile.
This commit is contained in:
guangli-dai 2022-12-01 17:31:08 -08:00 committed by Qi Wang
parent e8f9f13811
commit a74acb57e8
2 changed files with 29 additions and 18 deletions

View file

@ -28,6 +28,17 @@ timer_ratio(timedelta_t *a, timedelta_t *b, char *buf, size_t buflen) {
size_t i = 0;
size_t j, n;
/*
* The time difference could be 0 if the two clock readings are
* identical, either due to the operations being measured in the middle
* took very little time (or even got optimized away), or the clock
* readings are bad / very coarse grained clock.
* Thus, bump t1 if it is 0 to avoid dividing 0.
*/
if (t1 == 0) {
t1 = 1;
}
/* Whole. */
n = malloc_snprintf(&buf[i], buflen-i, "%"FMTu64, t0 / t1);
i += n;