Merge branch 'perf_net_dropmonitor'

Ben Hutchings says:

====================
Somewhat surprisingly, the net_dropmonitor reporting script doesn't work
at all.  This series fixes it and then makes it slightly more efficient.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Neil Horman <nhorman@tuxdriver.com>

1 files changed, 21 insertions, 18 deletions

diff --git a/tools/perf/scripts/python/net_dropmonitor.py b/tools/perf/scripts/python/net_dropmonitor.py
index a4ffc95..b574059 100755
--- a/tools/perf/scripts/python/net_dropmonitor.py
+++ b/tools/perf/scripts/python/net_dropmonitor.py
@@ -15,35 +15,38 @@ kallsyms = []
 
 def get_kallsyms_table():
 	global kallsyms
+
 	try:
 		f = open("/proc/kallsyms", "r")
-		linecount = 0
-		for line in f:
-			linecount = linecount+1
-		f.seek(0)
 	except:
 		return
 
-
-	j = 0
 	for line in f:
 		loc = int(line.split()[0], 16)
 		name = line.split()[2]
-		j = j +1
-		if ((j % 100) == 0):
-			print "\r" + str(j) + "/" + str(linecount),
-		kallsyms.append({ 'loc': loc, 'name' : name})
-
-	print "\r" + str(j) + "/" + str(linecount)
+		kallsyms.append((loc, name))
 	kallsyms.sort()
-	return
 
 def get_sym(sloc):
 	loc = int(sloc)
-	for i in kallsyms:
-		if (i['loc'] >= loc):
-			return (i['name'], i['loc']-loc)
-	return (None, 0)
+
+	# Invariant: kallsyms[i][0] <= loc for all 0 <= i <= start
+	#            kallsyms[i][0] > loc for all end <= i < len(kallsyms)
+	start, end = -1, len(kallsyms)
+	while end != start + 1:
+		pivot = (start + end) // 2
+		if loc < kallsyms[pivot][0]:
+			end = pivot
+		else:
+			start = pivot
+
+	# Now (start == -1 or kallsyms[start][0] <= loc)
+	# and (start == len(kallsyms) - 1 or loc < kallsyms[start + 1][0])
+	if start >= 0:
+		symloc, name = kallsyms[start]
+		return (name, loc - symloc)
+	else:
+		return (None, 0)
 
 def print_drop_table():
 	print "%25s %25s %25s" % ("LOCATION", "OFFSET", "COUNT")
@@ -64,7 +67,7 @@ def trace_end():
 
 # called from perf, when it finds a correspoinding event
 def skb__kfree_skb(name, context, cpu, sec, nsec, pid, comm,
-			skbaddr, protocol, location):
+		   skbaddr, location, protocol):
 	slocation = str(location)
 	try:
 		drop_log[slocation] = drop_log[slocation] + 1