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
diff --git a/absl/time/clock.cc b/absl/time/clock.cc
index 2bf53d9..aa74367 100644
--- a/absl/time/clock.cc
+++ b/absl/time/clock.cc
@@ -48,17 +48,16 @@
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"
