diff --git a/examples/bitehist.py b/examples/bitehist.py
index 55c902f09f3d..eb0518ad4be6 100755
--- a/examples/bitehist.py
+++ b/examples/bitehist.py
@@ -44,9 +44,6 @@ def usage():
 
 # header
 print("Tracing... Hit Ctrl-C to end.")
-last = {}
-for i in range(1, dist_max + 1):
-	last[i] = 0
 
 # functions
 stars_max = 38
@@ -67,7 +64,7 @@ def print_log2_hist(dist, val_type):
 	val_max = 0
 	for i in range(1, dist_max + 1):
 		try:
-			val = dist[c_int(i)].value - last[i]
+			val = dist[c_int(i)].value
 			if (val > 0):
 				idx_max = i
 			if (val > val_max):
@@ -82,10 +79,9 @@ def print_log2_hist(dist, val_type):
 		if (low == high):
 			low -= 1
 		try:
-			val = dist[c_int(i)].value - last[i]
+			val = dist[c_int(i)].value
 			print("%8d -> %-8d : %-8d |%-*s|" % (low, high, val,
 			    stars_max, stars(val, val_max, stars_max)))
-			last[i] = dist[c_int(i)].value
 		except:
 			break
 
@@ -104,5 +100,6 @@ def print_log2_hist(dist, val_type):
 
 	print
 	print_log2_hist(b["dist"], "kbytes")
+	b["dist"].clear()
 	if do_exit:
 		exit()
diff --git a/examples/vfsreadlat.py b/examples/vfsreadlat.py
index 7c28b9a5f32f..6c61c22551ea 100755
--- a/examples/vfsreadlat.py
+++ b/examples/vfsreadlat.py
@@ -45,9 +45,6 @@ def usage():
 
 # header
 print("Tracing... Hit Ctrl-C to end.")
-last = {}
-for i in range(1, dist_max + 1):
-	last[i] = 0
 
 # functions
 stars_max = 38
@@ -68,7 +65,7 @@ def print_log2_hist(dist, val_type):
 	val_max = 0
 	for i in range(1, dist_max + 1):
 		try:
-			val = dist[c_int(i)].value - last[i]
+			val = dist[c_int(i)].value
 			if (val > 0):
 				idx_max = i
 			if (val > val_max):
@@ -83,10 +80,9 @@ def print_log2_hist(dist, val_type):
 		if (low == high):
 			low -= 1
 		try:
-			val = dist[c_int(i)].value - last[i]
+			val = dist[c_int(i)].value
 			print("%8d -> %-8d : %-8d |%-*s|" % (low, high, val,
 			    stars_max, stars(val, val_max, stars_max)))
-			last[i] = dist[c_int(i)].value
 		except:
 			break
 
@@ -105,5 +101,6 @@ def print_log2_hist(dist, val_type):
 
 	print
 	print_log2_hist(b["dist"], "usecs")
+	b["dist"].clear()
 	if do_exit:
 		exit()
diff --git a/tools/pidpersec b/tools/pidpersec
index 2d3c731fe3e5..75ceaa754f6a 100755
--- a/tools/pidpersec
+++ b/tools/pidpersec
@@ -28,7 +28,6 @@ S_COUNT = c_int(1)
 print("Tracing... Ctrl-C to end.")
 
 # output
-last = 0
 while (1):
 	try:
 		sleep(1)
@@ -36,5 +35,5 @@ while (1):
 		exit()
 
 	print("%s: PIDs/sec: %d" % (strftime("%H:%M:%S"),
-	    (b["stats"][S_COUNT].value)))
+	    b["stats"][S_COUNT].value))
 	b["stats"].clear()
diff --git a/tools/vfsstat b/tools/vfsstat
index d44a9873ef51..d074faf607f1 100755
--- a/tools/vfsstat
+++ b/tools/vfsstat
@@ -54,11 +54,9 @@ stat_types = {
 
 # header
 print("%-8s  " % "TIME", end="")
-last = {}
 for stype in stat_types.keys():
 	print(" %8s" % (stype + "/s"), end="")
 	idx = stat_types[stype]
-	last[idx] = 0
 print("")
 
 # output
@@ -78,9 +76,9 @@ while (1):
 	for stype in stat_types.keys():
 		idx = stat_types[stype]
 		try:
-			delta = b["stats"][c_int(idx)].value - last[idx]
-			print(" %8d" % (delta / interval), end="")
-			last[idx] = b["stats"][c_int(idx)].value
+			val = b["stats"][c_int(idx)].value / interval
+			print(" %8d" % val, end="")
 		except:
 			print(" %8d" % 0, end="")
+	b["stats"].clear()
 	print("")