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/llwindow/llwindowwin32.cpp | 9 +++++++++
 1 file changed, 9 insertions(+)

(limited to 'indra/llwindow')

diff --git a/indra/llwindow/llwindowwin32.cpp b/indra/llwindow/llwindowwin32.cpp
index aadf895271..6beb874e8c 100644
--- a/indra/llwindow/llwindowwin32.cpp
+++ b/indra/llwindow/llwindowwin32.cpp
@@ -66,6 +66,7 @@
 
 #include <d3d9.h>
 #include <dxgi1_4.h>
+#include <timeapi.h>
 
 // Require DirectInput version 8
 #define DIRECTINPUT_VERSION 0x0800
@@ -4827,6 +4828,14 @@ void LLWindowWin32::LLWindowWin32Thread::run()
 
     initDX();
 
+    //as good a place as any to up the MM timer resolution (see ms_sleep)
+    //attempt to set timer resolution to 1ms
+    TIMECAPS tc;
+    if (timeGetDevCaps(&tc, sizeof(TIMECAPS)) == TIMERR_NOERROR)
+    {
+        timeBeginPeriod(llclamp((U32) 1, tc.wPeriodMin, tc.wPeriodMax));
+    }
+
     while (! getQueue().done())
     {
         LL_PROFILE_ZONE_SCOPED_CATEGORY_WIN32;
-- 
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