diff --git a/library/std/src/sys/thread/windows.rs b/library/std/src/sys/thread/windows.rs index 6a21b11e0312c..ea18572489ee0 100644 --- a/library/std/src/sys/thread/windows.rs +++ b/library/std/src/sys/thread/windows.rs @@ -8,7 +8,7 @@ use crate::sys::pal::time::WaitableTimer; use crate::sys::pal::{dur2timeout, to_u16s}; use crate::sys::{FromInner, c, stack_overflow}; use crate::thread::ThreadInit; -use crate::time::Duration; +use crate::time::{Duration, Instant}; use crate::{io, ptr}; pub const DEFAULT_MIN_STACK_SIZE: usize = 2 * 1024 * 1024; @@ -120,11 +120,28 @@ pub fn sleep(dur: Duration) { timer.set(dur)?; timer.wait() } + // Directly forward to `Sleep` for its zero duration behavior when indeed + // zero in order to skip the `Instant::now` calls, useless in this case. + if dur.is_zero() { + unsafe { c::Sleep(0) }; // Attempt to use high-precision sleep (Windows 10, version 1803+). - // On error fallback to the standard `Sleep` function. - // Also preserves the zero duration behavior of `Sleep`. - if dur.is_zero() || high_precision_sleep(dur).is_err() { - unsafe { c::Sleep(dur2timeout(dur)) } + // On error, fallback to the standard `Sleep` function. + } else if high_precision_sleep(dur).is_err() { + let start = Instant::now(); + unsafe { c::Sleep(dur2timeout(dur)) }; + + // See #149935: `Sleep` under Windows 7 and probably 8 as well seems a + // bit buggy for us as it can last less than the requested time while + // our API is meant to guarantee that. This is fixed by measuring the + // effective time difference and if needed, sleeping a bit more in + // order to ensure the duration is always exceeded. A fixed single + // millisecond works because `Sleep` operates based on a system-wide + // (until Windows 10 2004 that makes it process-local) interrupt timer + // that counts in "tick" units of ~15ms by default: a 1ms timeout + // therefore passes the next tick boundary. + if start.elapsed() < dur { + unsafe { c::Sleep(1) }; + } } }