diff options
Diffstat (limited to 'lib/qtime.c')
| -rw-r--r-- | lib/qtime.c | 14 |
1 files changed, 8 insertions, 6 deletions
diff --git a/lib/qtime.c b/lib/qtime.c index cdcf09f9..3e1e8269 100644 --- a/lib/qtime.c +++ b/lib/qtime.c @@ -47,7 +47,7 @@ * * The qtime_t value is in nano-seconds. * - * The result from times() is in units of sysconf(_SC_CLK_TCK). + * The result from times() is in units of sysconf(_SC_CLK_TCK) ticks per second. * * NB: it is assumed that qt_craft_monotonic will be called often enough to * ensure that it is not fooled by the clock wrapping round. @@ -61,7 +61,7 @@ * So this should be a safe assumption -- particularly as 60, 100, 250 and * 1000 ticks per second appear to be the popular options. * - * For safety, this asserts that the value is <= 1,000,000. + * For safety, this asserts that sysconf(_SC_CLK_TCK) <= 1,000,000. */ #ifdef GNU_LINUX @@ -89,12 +89,12 @@ qt_craft_monotonic(void) { /* clock either to jump or to get stuck ! */ #ifdef TIMES_TAKES_NULL - this_times_sample = times(NULL) ; /* assume this saves effort ! */ + this_times_sample = times(NULL) ; /* assume this saves effort ! */ #else this_times_sample = times(&dummy) ; #endif - if (this_times_sample == (clock_t)-1) + if (this_times_sample == (uint64_t)-1) /* deal with theoretical error */ { errno = 0 ; this_times_sample = times(&dummy) ; @@ -102,7 +102,10 @@ qt_craft_monotonic(void) { zabort_errno("times() failed") ; } ; + /* Advance the monotonic clock in sysconf(_SC_CLK_TCK) units. */ + monotonic += (this_times_sample - last_times_sample) ; + /* Set up times_scale_q & times_scale_q if not yet done */ if (times_clk_tcks == 0) /* Is zero until it's initialized */ { lldiv_t qr ; @@ -118,8 +121,7 @@ qt_craft_monotonic(void) { last_times_sample = this_times_sample ; } ; - monotonic += (this_times_sample - last_times_sample) ; - + /* Scale to qtime_t units. */ if (times_scale_r == 0) return monotonic * times_scale_q ; else |