WM: Switch to high-resolution timers on Windows for sleeping

This PR introduces a more precise sleep function `BLI_time_sleep_duration`
using high-resolution timers on Windows. By default, Windows only has a
resolution of 15.25ms for the regular `Sleep` function. Using more precise
timers makes sure that Blender can wake from sleep quicker and improves
performance at high frame rates.

High-resolution timers may have better energy efficiency than using
`timeBeginPeriod`/`timeEndPeriod` that change the timer resolution globally
on some versions of Windows.

Pull Request: https://projects.blender.org/blender/blender/pulls/140221

source/blender/blenlib/BLI_time.h

@@ -23,3 +23,11 @@ extern long int BLI_time_now_seconds_i(void);
  * \param ms: Number of milliseconds to sleep
  */
 void BLI_time_sleep_ms(int ms);
+
+/**
+ * Platform-independent high-resolution sleep function.
+ * Using this function can have advantages over \see BLI_time_sleep_ms on Windows due to a default
+ * non-precise sleep resolution of 15.25ms.
+ * \param us: Number of microseconds to sleep
+ */
+void BLI_time_sleep_precise_us(int us);

source/blender/blenlib/intern/time.cc

@@ -9,9 +9,16 @@
 #include "BLI_time.h"
 
 #ifdef WIN32
+
+#  include <cmath>
+#  include <cstdio>
+
 #  define WIN32_LEAN_AND_MEAN
 #  include <windows.h>
 
+/* timeapi.h needs to be included after windows.h. */
+#  include <timeapi.h>
+
 double BLI_time_now_seconds(void)
 {
   static int hasperfcounter = -1; /* (-1 == unknown) */
@@ -57,8 +64,49 @@ void BLI_time_sleep_ms(int ms)
   Sleep(ms);
 }
 
+void BLI_time_sleep_precise_us(int us)
+{
+  /* Prefer thread-safety over caching the timer with a static variable. According to
+   * https://github.com/rust-lang/rust/pull/116461/files, this costs only approximately 2000ns. */
+  HANDLE timerHandle = CreateWaitableTimerExW(
+      nullptr, nullptr, CREATE_WAITABLE_TIMER_HIGH_RESOLUTION, TIMER_ALL_ACCESS);
+  if (!timerHandle) {
+    if (GetLastError() == ERROR_INVALID_PARAMETER) {
+      /* CREATE_WAITABLE_TIMER_HIGH_RESOLUTION is only supported since Windows 10, version 1803. */
+      DWORD duration_ms = DWORD(std::ceil(double(us) / 1000.0));
+      Sleep(duration_ms);
+    }
+    else {
+      fprintf(stderr,
+              "BLI_time_sleep_precise_us: CreateWaitableTimerExW failed: %d\n",
+              GetLastError());
+    }
+    return;
+  }
+
+  /* Wait time is specified in 100 nanosecond intervals. */
+  LARGE_INTEGER wait_time;
+  wait_time.QuadPart = -us * 10;
+  if (!SetWaitableTimer(timerHandle, &wait_time, 0, nullptr, nullptr, 0)) {
+    fprintf(stderr, "BLI_time_sleep_precise_us: SetWaitableTimer failed: %d\n", GetLastError());
+    CloseHandle(timerHandle);
+    return;
+  }
+
+  if (WaitForSingleObject(timerHandle, INFINITE) != WAIT_OBJECT_0) {
+    fprintf(stderr, "BLI_time_sleep_precise_us: WaitForSingleObject failed: %d\n", GetLastError());
+    CloseHandle(timerHandle);
+    return;
+  }
+
+  CloseHandle(timerHandle);
+}
+
 #else
 
+#  include <chrono>
+#  include <thread>
+
 #  include <sys/time.h>
 #  include <unistd.h>
 
@@ -92,4 +140,9 @@ void BLI_time_sleep_ms(int ms)
   usleep(ms * 1000);
 }
 
+void BLI_time_sleep_precise_us(int us)
+{
+  std::this_thread::sleep_for(std::chrono::microseconds(us));
+}
+
 #endif

source/blender/windowmanager/intern/wm_window.cc

@@ -2003,21 +2003,7 @@ void wm_window_events_process(const bContext *C)
   /* Skip sleeping when simulating events so tests don't idle unnecessarily as simulated
    * events are typically generated from a timer that runs in the main loop. */
   if ((has_event == false) && (sleep_us != 0) && !(G.f & G_FLAG_EVENT_SIMULATE)) {
-    if (sleep_us == sleep_us_default) {
-      /* NOTE(@ideasman42): prefer #BLI_time_sleep_ms over `sleep_for(..)` in the common case
-       * because this function uses lower resolution (millisecond) resolution sleep timers
-       * which are tried & true for the idle loop. We could move to C++ `sleep_for(..)`
-       * if this works well on all platforms but this needs further testing. */
-      BLI_time_sleep_ms(sleep_us_default / 1000);
-    }
-    else {
-      /* The time was shortened to resume for the upcoming timer, use a high resolution sleep.
-       * Mainly happens during animation playback but could happen immediately before any timer.
-       *
-       * NOTE(@ideasman42): At time of writing Windows-10-22H2 doesn't give higher precision sleep.
-       * Keep the functionality as it doesn't have noticeable down sides either. */
-      std::this_thread::sleep_for(std::chrono::microseconds(sleep_us));
-    }
+    BLI_time_sleep_precise_us(sleep_us);
   }
 }