The comment above bintime2timespec() says: When converting between timestamps on parallel timescales of differing resolutions it is historical and scientific practice to round down.
However, the delta_nsec value is a time difference and not a timestamp. Also the rounding errors accumulate in the frequency accumulator, see hardpps(). So, rounding to the closest integer is probably slightly better. Reviewed by: imp Pull Request: https://github.com/freebsd/freebsd-src/pull/604 --- cpukit/score/src/kern_tc.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/cpukit/score/src/kern_tc.c b/cpukit/score/src/kern_tc.c index 0aa0fdd393..95ae01b5b4 100644 --- a/cpukit/score/src/kern_tc.c +++ b/cpukit/score/src/kern_tc.c @@ -2266,6 +2266,7 @@ pps_event(struct pps_state *pps, int event) #ifdef PPS_SYNC if (fhard) { uint64_t delta_nsec; + uint64_t freq; /* * Feed the NTP PLL/FLL. @@ -2277,7 +2278,8 @@ pps_event(struct pps_state *pps, int event) tcount &= captc->tc_counter_mask; delta_nsec = 1000000000; delta_nsec *= tcount; - delta_nsec /= captc->tc_frequency; + freq = captc->tc_frequency; + delta_nsec = (delta_nsec + freq / 2) / freq; hardpps(tsp, (long)delta_nsec); } #endif -- 2.35.3 _______________________________________________ devel mailing list devel@rtems.org http://lists.rtems.org/mailman/listinfo/devel
