From ec5009d70eb0fd729126b2321b9d7d6118741573 Mon Sep 17 00:00:00 2001
From: Dave Parks <davep@lindenlab.com>
Date: Thu, 13 Oct 2022 19:51:40 -0500
Subject: SL-18190 Potential fix for sapping CPU when "sleeping"

---
 indra/llcommon/lltimer.cpp | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

(limited to 'indra/llcommon')

diff --git a/indra/llcommon/lltimer.cpp b/indra/llcommon/lltimer.cpp
index 39dfee3755..8739eeef00 100644
--- a/indra/llcommon/lltimer.cpp
+++ b/indra/llcommon/lltimer.cpp
@@ -65,6 +65,9 @@ LLTimer* LLTimer::sTimer = NULL;
 //---------------------------------------------------------------------------
 
 #if LL_WINDOWS
+
+
+#if 0
 void ms_sleep(U32 ms)
 {
     LL_PROFILE_ZONE_SCOPED;
@@ -83,6 +86,31 @@ U32 micro_sleep(U64 us, U32 max_yields)
 	ms_sleep((U32)(us / 1000));
     return 0;
 }
+
+#else
+
+U32 micro_sleep(U64 us, U32 max_yields)
+{
+    LL_PROFILE_ZONE_SCOPED
+    LARGE_INTEGER ft;
+    ft.QuadPart = -static_cast<S64>(us * 10);  // '-' using relative time
+
+    HANDLE timer = CreateWaitableTimer(NULL, TRUE, NULL);
+    SetWaitableTimer(timer, &ft, 0, NULL, NULL, 0);
+    WaitForSingleObject(timer, INFINITE);
+    CloseHandle(timer);
+
+    return 0;
+}
+
+void ms_sleep(U32 ms)
+{
+    LL_PROFILE_ZONE_SCOPED
+    micro_sleep(ms * 1000, 0);
+}
+
+#endif
+
 #elif LL_LINUX || LL_DARWIN
 static void _sleep_loop(struct timespec& thiswait)
 {
-- 
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