repair rate computation across resets.

This repair is mathematically correct so the user can now
check the sign bit to detect counter resets. The loss
of information during the interval of a counter reset
is the user's problem to bound.

ldms/src/sampler/sysclassib.c

@@ -310,7 +310,7 @@ static int create_metric_set(const char *instance_name, char *schema_name)
 					port->ca,
 					port->portno);
 				port->rate[i] = ldms_schema_metric_add(schema, metric_name,
-							LDMS_V_F32);
+							LDMS_V_D64);
 			}
 		}
 	}
@@ -641,21 +641,21 @@ static ldms_set_t get_set(struct ldmsd_sampler *self)
  */
 static
 inline void update_metric(struct scib_port *port, int idx, uint64_t new_v,
-			float dt)
+			double dt)
 {
 	uint64_t old_v = ldms_metric_get_u64(set, port->handle[idx]);
 	if (!port->ext)
 		new_v += old_v;
 	ldms_metric_set_u64(set, port->handle[idx], new_v);
 	if (sysclassib_metrics_type == SYSCLASSIB_METRICS_BOTH) {
-		ldms_metric_set_float(set, port->rate[idx], (new_v - old_v) / dt);
+		ldms_metric_set_double(set, port->rate[idx], ((double)new_v - (double)old_v) / dt);
 	}
 }
 
 /**
  * Port query (utility function).
  */
-int query_port(struct scib_port *port, float dt)
+int query_port(struct scib_port *port, double dt)
 {
 	void *p;
 	int rc;
@@ -733,7 +733,7 @@ static int sample(struct ldmsd_sampler *self)
 {
 	struct timeval *tmp;
 	struct timeval tv_diff;
-	float dt;
+	double dt;
 	struct scib_port *port;
 
 	if (!set) {
@@ -743,7 +743,7 @@ static int sample(struct ldmsd_sampler *self)
 
 	gettimeofday(tv_now, 0);
 	timersub(tv_now, tv_prev, &tv_diff);
-	dt = tv_diff.tv_sec + tv_diff.tv_usec / 1e06f;
+	dt = (double)tv_diff.tv_sec + tv_diff.tv_usec / 1.0e06;
 
 	ldms_transaction_begin(set);
 	LJI_SAMPLE(set,1);