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| author | Derek Mauro <dmauro@google.com> | 2023-05-26 09:43:35 -0700 |
|---|---|---|
| committer | Copybara-Service <copybara-worker@google.com> | 2023-05-26 09:44:21 -0700 |
| commit | 8e45685002488b55f24cb67a795eaa8d1c3297a1 (patch) | |
| tree | 84e57b593ab6a683ba7a6e5d4975e241089cfb18 /absl/time | |
| parent | 0f718c568b448005bcb6718e7c0f5b6420ace413 (diff) | |
| download | abseil-8e45685002488b55f24cb67a795eaa8d1c3297a1.tar.gz abseil-8e45685002488b55f24cb67a795eaa8d1c3297a1.tar.bz2 abseil-8e45685002488b55f24cb67a795eaa8d1c3297a1.zip | |
Disable the use of the fast GetCurrentTimeNanos() algorithm based on
the cyclecounter by default, since it may be unsafe in some situations
(for example, if the system may enter a sleep state).
Fixes #1460
PiperOrigin-RevId: 535641718
Change-Id: I41c9cc4bc7a8ae7280ff9df00abd57668205045b
Diffstat (limited to 'absl/time')
| -rw-r--r-- | absl/time/clock.cc | 13 |
1 files changed, 6 insertions, 7 deletions
diff --git a/absl/time/clock.cc b/absl/time/clock.cc index 2bf53d9c..aa74367b 100644 --- a/absl/time/clock.cc +++ b/absl/time/clock.cc @@ -48,17 +48,16 @@ Time Now() { ABSL_NAMESPACE_END } // namespace absl -// Decide if we should use the fast GetCurrentTimeNanos() algorithm -// based on the cyclecounter, otherwise just get the time directly -// from the OS on every call. This can be chosen at compile-time via +// Decide if we should use the fast GetCurrentTimeNanos() algorithm based on the +// cyclecounter, otherwise just get the time directly from the OS on every call. +// By default, the fast algorithm based on the cyclecount is disabled because in +// certain situations, for example, if the OS enters a "sleep" mode, it may +// produce incorrect values immediately upon waking. +// This can be chosen at compile-time via // -DABSL_USE_CYCLECLOCK_FOR_GET_CURRENT_TIME_NANOS=[0|1] #ifndef ABSL_USE_CYCLECLOCK_FOR_GET_CURRENT_TIME_NANOS -#if ABSL_USE_UNSCALED_CYCLECLOCK -#define ABSL_USE_CYCLECLOCK_FOR_GET_CURRENT_TIME_NANOS 1 -#else #define ABSL_USE_CYCLECLOCK_FOR_GET_CURRENT_TIME_NANOS 0 #endif -#endif #if defined(__APPLE__) || defined(_WIN32) #include "absl/time/internal/get_current_time_chrono.inc" |