speed up gb by fixing excessive calling to

gettimeofday() system call.

Loop.cpp

@@ -929,9 +929,10 @@ bool Loop::init ( ) {
 
 
 	m_realInterrupt.it_value.tv_sec = 0;
-	m_realInterrupt.it_value.tv_usec = 10 * 1000;
+	// 1000 microseconds in a millisecond
+	m_realInterrupt.it_value.tv_usec = 1 * 1000;
 	m_realInterrupt.it_interval.tv_sec = 0;
-	m_realInterrupt.it_interval.tv_usec = 10 * 1000;
+	m_realInterrupt.it_interval.tv_usec = 1 * 1000;
 
 
  	m_noInterrupt.it_value.tv_sec = 0;
@@ -1148,6 +1149,9 @@ void sigvtalrmHandler ( int x , siginfo_t *info , void *y ) {
 
 void sigalrmHandler ( int x , siginfo_t *info , void *y ) {
 
+	// so we don't call gettimeofday() thousands of times a second...
+	g_clockNeedsUpdate = true;
+
 	// stats
 	g_numAlarms++;
 	// . see where we are in the code

Profiler.cpp

@@ -1438,6 +1438,16 @@ extern int g_inMemcpy;
 void
 Profiler::getStackFrame(int sig) {
 
+	// need to interrupt every 1ms to set this to true
+	g_clockNeedsUpdate = true;
+
+	// profile once every 5ms, not every 1ms
+	static int32_t s_count = 0;
+
+	if ( ++s_count != 5 ) return;
+
+	s_count = 0;
+
 	// prevent cores.
 	// TODO: hack this to a function somehow...
 	// we set this to positive values when calling library functions like
@@ -1566,9 +1576,10 @@ Profiler::startRealTimeProfiler() {
 	//signal(SIGVTALRM, Profiler::getStackFrame);
 	signal(SIGALRM, Profiler::getStackFrame);
 	value.it_interval.tv_sec = 0;
-	value.it_interval.tv_usec = 5000;
+	// 1000 microseconds is 1 millisecond
+	value.it_interval.tv_usec = 1000;
 	value.it_value.tv_sec = 0;
-	value.it_value.tv_usec = 5000;
+	value.it_value.tv_usec = 1000;
 	setitimer( which, &value, &ovalue );
 	m_realTimeProfilerRunning = true;
 }

fctypes.cpp

@@ -10,6 +10,8 @@
 
 static bool g_clockInSync = false;
 
+bool g_clockNeedsUpdate = true;
+
 bool isClockInSync() { 
 	if ( g_hostdb.m_initialized && g_hostdb.m_hostId == 0 ) return true;
 	return g_clockInSync; 
@@ -1938,6 +1940,14 @@ int64_t gettimeofdayInMilliseconds() {
 	// a signal handler is underway in the main thread!
 	if ( g_inSigHandler && ! g_threads.amThread() ) { 
 		char *xx = NULL; *xx = 0; }
+
+	// the real tiem sigalrm interrupt in Loop.cpp sets this to
+	// true once per millisecond
+	if ( ! g_clockNeedsUpdate )
+		return g_now;
+
+	g_clockNeedsUpdate = false;
+
 	// this isn't async signal safe...
 	struct timeval tv;
 	//g_loop.disableTimer();

fctypes.h

@@ -7,6 +7,8 @@
 #include <math.h>      // floor()
 #include "Unicode.h"
 
+extern bool g_clockNeedsUpdate;
+
 // we have to leave this as 32 bits for now because the termlists store
 // the hash value as 32 bits in posdb
 typedef uint32_t FacetValHash_t;