DEV-45468 SNOW-108: Fast timers are broken / badly-scaled on linux

more reliable fix based on feedback from Richard.  dicked with the Darwin results too since those seemed wrong based on the same feedback (also covered in test plan).

indra/llcommon/llfasttimer.h

@@ -113,7 +113,7 @@ inline U64 LLFastTimer::getCPUClockCount64()
 	struct timespec tp;
 	
 #ifdef CLOCK_MONOTONIC // MONOTONIC supported at build-time?
-	if (-1 == clock_gettime(CLOCK_MONOTONIC,&tp)) // if MONOTONIC isn't supported at runtime, try REALTIME
+	if (-1 == clock_gettime(CLOCK_MONOTONIC,&tp)) // if MONOTONIC isn't supported at runtime then ouch, try REALTIME
 #endif
 		clock_gettime(CLOCK_REALTIME,&tp);
 
@@ -122,7 +122,7 @@ inline U64 LLFastTimer::getCPUClockCount64()
 
 inline U32 LLFastTimer::getCPUClockCount32()
 {
-	return (U32)LLFastTimer::getCPUClockCount64();
+	return (U32)(LLFastTimer::getCPUClockCount64() >> 8);
 }
 #endif // (LL_LINUX || LL_SOLARIS))
 
@@ -134,14 +134,14 @@ inline U32 LLFastTimer::getCPUClockCount32()
 {
 	U64 x;
 	__asm__ volatile (".byte 0x0f, 0x31": "=A"(x));
-	return (U32)x >> 8;
+	return (U32)(x >> 8);
 }
 
 inline U64 LLFastTimer::getCPUClockCount64()
 {
 	U64 x;
 	__asm__ volatile (".byte 0x0f, 0x31": "=A"(x));
-	return x >> 8;
+	return x;
 }
 #endif
 
@@ -154,7 +154,7 @@ inline U64 LLFastTimer::getCPUClockCount64()
 
 inline U32 LLFastTimer::getCPUClockCount32()
 {
-	return (U32)get_clock_count();
+	return (U32)(get_clock_count()>>8);
 }
 
 inline U64 LLFastTimer::getCPUClockCount64()

indra/llcommon/llfasttimer_class.cpp

@@ -226,12 +226,12 @@ void LLFastTimer::DeclareTimer::updateCachedPointers()
 
 //static
 #if LL_LINUX || LL_SOLARIS || ( LL_DARWIN && !(defined(__i386__) || defined(__amd64__)) )
-U64 LLFastTimer::countsPerSecond()
+U64 LLFastTimer::countsPerSecond() // counts per second for the *32-bit* timer
 {
-	return sClockResolution;
+	return sClockResolution >> 8;
 }
 #else // windows or x86-mac
-U64 LLFastTimer::countsPerSecond()
+U64 LLFastTimer::countsPerSecond() // counts per second for the *32-bit* timer
 {
 	static U64 sCPUClockFrequency = U64(CProcessor().GetCPUFrequency(50));