X-Git-Url: https://git.kernel.dk/?a=blobdiff_plain;f=stat.c;h=a665ec8f03cb72092bdb39b769011331a861b9eb;hb=687040842bf56502d33b6c0cb5d2af6da27d080c;hp=b4facc7eab4da21a71ff7f343f7e2f264ab9ea40;hpb=1e97cce9f5a87a67293a05ec4533ed6968698b2e;p=fio.git

diff --git a/stat.c b/stat.c
index b4facc7e..a665ec8f 100644
--- a/stat.c
+++ b/stat.c
@@ -94,14 +94,26 @@ static int disk_util_exists(dev_t dev)
 
 static void disk_util_add(dev_t dev, char *path)
 {
-	struct disk_util *du = malloc(sizeof(*du));
+	struct disk_util *du, *__du;
+	struct list_head *entry;
 
+	du = malloc(sizeof(*du));
 	memset(du, 0, sizeof(*du));
 	INIT_LIST_HEAD(&du->list);
 	sprintf(du->path, "%s/stat", path);
 	du->name = strdup(basename(path));
 	du->dev = dev;
 
+	list_for_each(entry, &disk_list) {
+		__du = list_entry(entry, struct disk_util, list);
+
+		if (!strcmp(du->name, __du->name)) {
+			free(du->name);
+			free(du);
+			return;
+		}
+	}
+
 	fio_gettime(&du->time, NULL);
 	get_io_ticks(du, &du->last_dus);
 
@@ -271,7 +283,7 @@ void update_rusage_stat(struct thread_data *td)
 static int calc_lat(struct io_stat *is, unsigned long *min, unsigned long *max,
 		    double *mean, double *dev)
 {
-	double n;
+	double n = is->samples;
 
 	if (is->samples == 0)
 		return 0;
@@ -280,8 +292,12 @@ static int calc_lat(struct io_stat *is, unsigned long *min, unsigned long *max,
 	*max = is->max_val;
 
 	n = (double) is->samples;
-	*mean = (double) is->val / n;
-	*dev = sqrt(((double) is->val_sq - (*mean * *mean) / n) / (n - 1));
+	*mean = is->mean;
+
+	if (n > 1.0)
+		*dev = sqrt(is->S / (n - 1.0));
+	else
+		*dev = -1.0;
 
 	return 1;
 }
@@ -529,15 +545,21 @@ void show_run_stats(void)
 	free(runstats);
 }
 
-static inline void add_stat_sample(struct io_stat *is, unsigned long val)
+static inline void add_stat_sample(struct io_stat *is, unsigned long data)
 {
-	if (val > is->max_val)
-		is->max_val = val;
-	if (val < is->min_val)
-		is->min_val = val;
+	double val = data;
+	double delta, n;
+
+	if (data > is->max_val)
+		is->max_val = data;
+	if (data < is->min_val)
+		is->min_val = data;
+
+	delta = val - is->mean;
+	n = is->samples + 1.0;
+	is->mean += delta / n;
+	is->S += delta * (val - is->mean);
 
-	is->val += val;
-	is->val_sq += val * val;
 	is->samples++;
 }