From e92e4d8b505b4707c2692b1ea3b2a13370a4d2d3 Mon Sep 17 00:00:00 2001
From: Sam Lantinga <[EMAIL REDACTED]>
Date: Tue, 23 May 2023 11:32:40 -0700
Subject: [PATCH] Save waitable timers in thread local storage instead of
continuously allocating and freeing them
Fixes https://github.com/libsdl-org/SDL/issues/6597
---
src/timer/windows/SDL_systimer.c | 28 ++++++++++++++++++++++++++--
1 file changed, 26 insertions(+), 2 deletions(-)
diff --git a/src/timer/windows/SDL_systimer.c b/src/timer/windows/SDL_systimer.c
index 15c872e68dd2..8dd6057ea4c2 100644
--- a/src/timer/windows/SDL_systimer.c
+++ b/src/timer/windows/SDL_systimer.c
@@ -25,6 +25,31 @@
#include "../../core/windows/SDL_windows.h"
+#ifdef CREATE_WAITABLE_TIMER_HIGH_RESOLUTION
+static void SDL_CleanupWaitableTimer(void *timer)
+{
+ CloseHandle(timer);
+}
+
+HANDLE SDL_GetWaitableTimer()
+{
+ static SDL_TLSID TLS_timer_handle;
+ HANDLE timer;
+
+ if (!TLS_timer_handle) {
+ TLS_timer_handle = SDL_TLSCreate();
+ }
+ timer = SDL_TLSGet(TLS_timer_handle);
+ if (!timer) {
+ timer = CreateWaitableTimerExW(NULL, NULL, CREATE_WAITABLE_TIMER_HIGH_RESOLUTION, TIMER_ALL_ACCESS);
+ if (timer) {
+ SDL_TLSSet(TLS_timer_handle, timer, SDL_CleanupWaitableTimer);
+ }
+ }
+ return timer;
+}
+#endif /* CREATE_WAITABLE_TIMER_HIGH_RESOLUTION */
+
Uint64 SDL_GetPerformanceCounter(void)
{
LARGE_INTEGER counter;
@@ -58,14 +83,13 @@ void SDL_DelayNS(Uint64 ns)
* apps and libraries.
*/
#ifdef CREATE_WAITABLE_TIMER_HIGH_RESOLUTION
- HANDLE timer = CreateWaitableTimerExW(NULL, NULL, CREATE_WAITABLE_TIMER_HIGH_RESOLUTION, TIMER_ALL_ACCESS);
+ HANDLE timer = SDL_GetWaitableTimer();
if (timer) {
LARGE_INTEGER due_time;
due_time.QuadPart = -((LONGLONG)ns / 100);
if (SetWaitableTimerEx(timer, &due_time, 0, NULL, NULL, NULL, 0)) {
WaitForSingleObject(timer, INFINITE);
}
- CloseHandle(timer);
return;
}
#endif