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>

diff --git a/tools/perf/scripts/python/net_dropmonitor.py b/tools/perf/scripts/python/net_dropmonitor.py
index a4ffc95..b574059 100755 (executable)
--- 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