diff --git a/include/Utils.h b/include/Utils.h

index 75238911d..1b584883d 100755

--- include/Utils.h

+++ include/Utils.h

@@ -58,6 +58,7 @@ public:

   static u_int32_t hashString(const char * const s);

   static float timeval2ms(struct timeval *tv);

   static float msTimevalDiff(const struct timeval *end, const struct timeval *begin);

+  static u_int32_t usecTimevalDiff(const struct timeval *end, const struct timeval *begin);

   static size_t file_write(const char *path, const char *content, size_t content_len);

   static size_t file_read(const char *path, char **content);

   static bool file_exists(const char * const path);

diff --git a/src/Ntop.cpp b/src/Ntop.cpp

index 5ca6a1f69..3cdfda3b1 100644

--- src/Ntop.cpp

+++ src/Ntop.cpp

@@ -547,7 +547,7 @@ void Ntop::start() {

   _usleep((5 - begin.tv_sec % 5) * 1e6 - begin.tv_usec);

   while((!globals->isShutdown()) && (!globals->isShutdownRequested())) {

-    u_long nap = ntop->getPrefs()->get_housekeeping_frequency() * 1e6;

+    const u_int32_t nap_usec = ntop->getPrefs()->get_housekeeping_frequency() * 1e6;

     gettimeofday(&begin, NULL);

@@ -566,35 +566,39 @@ void Ntop::start() {

     runHousekeepingTasks();

+#ifndef __linux__

+    gettimeofday(&end, NULL);

+    

+    usec_diff = Utils::usecTimevalDiff(&end, &begin);

+

+    if(usec_diff < nap_usec)

+      _usleep(nap_usec-usec_diff);

+#else

     do {

       gettimeofday(&end, NULL);

+      usec_diff = Utils::usecTimevalDiff(&end, &begin);

-      usec_diff = (end.tv_sec * 1e6) + end.tv_usec - (begin.tv_sec * 1e6) - begin.tv_usec;

-

-      if(usec_diff < nap) {

+      if(usec_diff < nap_usec) {

         int maxfd = 0;

         fd_set rset;

         struct timeval tv;

 #if 0

-        ntop->getTrace()->traceEvent(TRACE_DEBUG,

+        ntop->getTrace()->traceEvent(TRACE_NORMAL,

             "Sleeping %i microsecods before doing the chores.",

-            (nap - usec_diff));

+            (nap_usec - usec_diff));

 #endif

         FD_ZERO(&rset);

-#ifdef __linux__

         if(inotify_fd > 0) {

           FD_SET(inotify_fd, &rset);

           maxfd = inotify_fd;

         }

-#endif

-        tv.tv_sec = 0, tv.tv_usec = (nap - usec_diff);

+        tv.tv_sec = 0, tv.tv_usec = (nap_usec - usec_diff);

         if(select(maxfd + 1, &rset, NULL, NULL, &tv) > 0) {

-#ifdef __linux__

           if(FD_ISSET(inotify_fd, &rset)) {

             char buffer[EVENT_BUF_LEN];

@@ -604,10 +608,10 @@ void Ntop::start() {

             ntop->getTrace()->traceEvent(TRACE_DEBUG, "Directory changed");

             reloadPeriodicScripts();

           }

-#endif

         }

       }

-    } while(usec_diff < nap);

+    } while(usec_diff < nap_usec);

+#endif    

   }

 }

diff --git a/src/Utils.cpp b/src/Utils.cpp

index 4761c843f..4e3b50fc2 100755

--- src/Utils.cpp

+++ src/Utils.cpp

@@ -436,6 +436,25 @@ u_int32_t Utils::timeval2usec(const struct timeval *tv) {

 /* ****************************************************** */

+u_int32_t Utils::usecTimevalDiff(const struct timeval *end, const struct timeval *begin) {

+  if((end->tv_sec == 0) && (end->tv_usec == 0))

+    return(0);

+  else {

+    struct timeval res;

+    

+    res.tv_sec = end->tv_sec - begin->tv_sec;

+    if(begin->tv_usec > end->tv_usec) {

+      res.tv_usec = end->tv_usec + 1000000 - begin->tv_usec;

+      res.tv_sec--;

+    } else

+      res.tv_usec = end->tv_usec - begin->tv_usec;

+

+    return((res.tv_sec*1000000) + (res.tv_usec));

+  }

+}

+

+/* ****************************************************** */

+

 float Utils::msTimevalDiff(const struct timeval *end, const struct timeval *begin) {

   if((end->tv_sec == 0) && (end->tv_usec == 0))

     return(0);