From 98f909f9915448d49cd7fe83d044fdc490fc6003 Mon Sep 17 00:00:00 2001
From: Jacek Antonelli
Date: Wed, 18 Nov 2009 23:08:01 -0600
Subject: SNOW-108: Fast timers fail on non i386 systems

Patch by Robin Cornelius
---
 ChangeLog.txt                         |  8 ++++++++
 linden/doc/contributions.txt          |  1 +
 linden/indra/llcommon/llfasttimer.cpp | 35 +++++++++++++++++++++++++----------
 linden/indra/llcommon/llfasttimer.h   |  1 +
 4 files changed, 35 insertions(+), 10 deletions(-)

diff --git a/ChangeLog.txt b/ChangeLog.txt
index 492d353..cc20925 100644
--- a/ChangeLog.txt
+++ b/ChangeLog.txt
@@ -1,5 +1,13 @@
 2009-11-18  Jacek Antonelli  <jacek.antonelli@gmail.com>
 
+	* SNOW-108: Fast timers fail on non i386 systems
+	  Patch by Robin Cornelius
+
+	  modified:   doc/contributions.txt
+	  modified:   indra/llcommon/llfasttimer.cpp
+	  modified:   indra/llcommon/llfasttimer.h
+
+
 	* Added "File > Export Selected Objects..."
 
 	  modified:   linden/indra/newview/skins/default/xui/en-us/menu_viewer.xml
diff --git a/linden/doc/contributions.txt b/linden/doc/contributions.txt
index 64304dc..e99bd78 100644
--- a/linden/doc/contributions.txt
+++ b/linden/doc/contributions.txt
@@ -347,6 +347,7 @@ princess niven
 Renault Clio
 	VWR-1976
 Robin Cornelius
+	SNOW-108
 	VWR-2488
 Ryozu Kojima
 	VWR-287
diff --git a/linden/indra/llcommon/llfasttimer.cpp b/linden/indra/llcommon/llfasttimer.cpp
index 3304528..9253f2b 100644
--- a/linden/indra/llcommon/llfasttimer.cpp
+++ b/linden/indra/llcommon/llfasttimer.cpp
@@ -63,6 +63,12 @@ int LLFastTimer::sResetHistory = 0;
 
 F64 LLFastTimer::sCPUClockFrequency = 0.0;
 
+#if LL_LINUX || LL_SOLARIS
+U64 LLFastTimer::sClockResolution = 1e9; // Nanosecond resolution
+#else 
+U64 LLFastTimer::sClockResolution = 1e6; // Microsecond resolution
+#endif
+
 //////////////////////////////////////////////////////////////////////////////
 
 //
@@ -90,17 +96,26 @@ U64 get_cpu_clock_count()
 
 #endif // LL_WINDOWS
 
-
-#if (LL_LINUX || LL_SOLARIS) && (defined(__i386__) || defined(__amd64__))
+#if LL_LINUX || LL_SOLARIS
+// Try to use the MONOTONIC clock if available, this is a constant time counter
+// with nanosecond resolution (but not necessarily accuracy) and attempts are made
+// to synchronize this value between cores at kernel start. It should not be effected
+// by CPU frequency. If not available use the REALTIME clock, but this may be effected by
+// NTP adjustments or other user activity effecting the system time.
 U64 get_cpu_clock_count()
 {
-	U64 x;
-	__asm__ volatile (".byte 0x0f, 0x31" : "=A" (x));
-	return x;
-}
+    struct timespec tp;
+
+#ifdef CLOCK_MONOTONIC
+    clock_gettime(CLOCK_MONOTONIC,&tp);
+#else
+    clock_gettime(CLOCK_REALTIME,&tp);
 #endif
+    return (tp.tv_sec*LLFastTimer::sClockResolution)+tp.tv_nsec;        
+}
+#endif // (LL_LINUX || LL_SOLARIS))
 
-#if LL_DARWIN || (LL_SOLARIS && defined(__sparc__))
+#if LL_DARWIN
 //
 // Mac implementation of CPU clock
 //
@@ -115,13 +130,13 @@ U64 get_cpu_clock_count()
 //////////////////////////////////////////////////////////////////////////////
 
 //static
-#if LL_LINUX || LL_DARWIN || LL_SOLARIS
+#if LL_DARWIN || LL_LINUX || LL_SOLARIS
 // Both Linux and Mac use gettimeofday for accurate time
 U64 LLFastTimer::countsPerSecond()
 {
-	return 1000000; // microseconds, so 1 Mhz.
+	return sClockResolution; // microseconds, so 1 Mhz.
 }
-#else
+#else 
 U64 LLFastTimer::countsPerSecond()
 {
 	if (!sCPUClockFrequency)
diff --git a/linden/indra/llcommon/llfasttimer.h b/linden/indra/llcommon/llfasttimer.h
index a32da18..2e66496 100644
--- a/linden/indra/llcommon/llfasttimer.h
+++ b/linden/indra/llcommon/llfasttimer.h
@@ -238,6 +238,7 @@ public:
 	static int sPauseHistory;
 	static int sResetHistory;
 	static F64 sCPUClockFrequency;
+    static U64 sClockResolution;
 	
 private:
 	EFastTimerType mType;
-- 
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