Summary:
The original implementation of WinEnvIO::NowNanos() has a constant data overflow by:
li.QuadPart *= std::nano::den;
As a result, the api provides a incorrect result.
e.g.:
li.QuadPart=13477844301545
std::nano::den=1e9
The fix uses pre-computed nano_seconds_per_period_ to present the nano seconds per performance counter period, in the case if nano::den is divisible by perf_counter_frequency_. Otherwise it falls back to use high_resolution_clock.
siying ajkr
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5062
Differential Revision: D14426842
Pulled By: anand1976
fbshipit-source-id: 127f1daf423dd4b30edd0dcf8ea0466f468bec12
88d85b6820