maint: Replace usage of folly in clock.hpp
#1448
Conversation
There was a problem hiding this comment.
Is is possible to check if the resolution of the clock is the same?
There was a problem hiding this comment.
Both have nanoseconds resolution seemingly calling clock_gettime.
There was a problem hiding this comment.
folly::chrono::clock_gettime_ns's definition uses the vDSO on Linux (calling the vDSO is not considered a good practice (see the "Description" section of vdso(7)'s man page). Alternatively, it calls clock_gettime.
std::chrono::system_clock::now has nanosecond precision. and also calls clock_gettime with CLOCK_REALTIME.
The only drawback is that coarse_nanos_since_epoch who used to return coarse precision timestamp (see CLOCK_REALTIME_COARSE) now returns an accurate timestamp. Must we refine it or not?
Signed-off-by: Julien Jerphanion <[email protected]>
jjerphan
force-pushed
the
maint/replace-folly-usage-in-clock.hpp
branch
2 times, most recently
from
0785fd2
to
12d7671
Compare
Signed-off-by: Julien Jerphanion <[email protected]> Co-authored-by: William Dealtry <[email protected]>
Reference Issues/PRs
Part of #1412.
What does this implement or fix?
folly::chrono::clock_gettime_ns's definition uses the vDSO on Linux (calling the vDSO is not considered a good practice (see the "Description" section ofvdso(7)'s man page). Alternatively, it callsclock_gettime.std::chrono::system_clock::nowhas nanosecond precision. and also callsclock_gettimewithCLOCK_REALTIME.libstdc++does not useCLOCK_REALTIME_COARSEat all..Hence, the only drawback is that
coarse_nanos_since_epochwho used to return coarse precision timestamp (seeCLOCK_REALTIME_COARSE) now returns an accurate timestamp. Must we keep coarse precision or not?Any other comments?
Checklist
Checklist for code changes...