ff_kern_timeout: optimize the timecounter.

This timecounter implementation retrieves the current time and reports it
as the equivalent number of counts from a counter incrementing at 'hz'.

freebsd/vm/uma_core.c

@@ -462,9 +462,6 @@ zone_foreach_keg(uma_zone_t zone, void (*kegfn)(uma_keg_t))
 static void
 uma_timeout(void *unused)
 {
-#ifdef FSTACK
-    return;
-#endif
 	bucket_enable();
 	zone_foreach(zone_timeout);
 

lib/ff_dpdk_if.c

@@ -1597,3 +1597,12 @@ ff_regist_packet_dispatcher(dispatch_func_t func)
 {
     packet_dispatcher = func;
 }
+
+uint64_t
+ff_get_tsc_ns()
+{
+    uint64_t cur_tsc = rte_rdtsc();
+    uint64_t hz = rte_get_tsc_hz();
+    return ((double)cur_tsc/(double)hz) * NS_PER_S;
+}
+

lib/ff_host_interface.c

@@ -176,9 +176,14 @@ ff_clock_gettime_ns(int id)
 void
 ff_get_current_time(time_t *sec, long *nsec)
 {
+    if (sec) {
         *sec = current_ts.tv_sec;
+    }
+
+    if (nsec) {
         *nsec = current_ts.tv_nsec;
     }
+}
 
 void
 ff_update_current_ts()

lib/ff_host_interface.h

@@ -56,6 +56,7 @@ void ff_free(void *p);
 
 void ff_clock_gettime(int id, int64_t *sec, long *nsec);
 uint64_t ff_clock_gettime_ns(int id);
+uint64_t ff_get_tsc_ns(void);
 
 void ff_get_current_time(int64_t *sec, long *nsec);
 void ff_update_current_ts(void);

lib/ff_kern_timeout.c

@@ -1657,8 +1657,9 @@ ff_hardclock(void)
 static unsigned int
 ff_tc_get_timecount(struct timecounter *tc)
 {
-    static u_int now;
-    return (++now);
+    uint64_t ns;
+    ns = ff_get_tsc_ns();
+    return ((ns * tc->tc_frequency) / ff_NSEC_PER_SEC);
 }
 
 static struct timecounter ff_timecounter = {