perf script: Add drop monitor script

A while back I created the dropmonitor protocol, which allowed users to get
reports of dropped frames communicated to them via a netlink socket.

While useful, several people have now asked that I integrate the ability
to do drop monitoring with perf, so they don't have to run additional
tools.

This patch adds a drop monitor script to the perf suite, and provides
the same output that the netlink socket does.

Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1309801217-22450-1-git-send-email-nhorman@tuxdriver.com
Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/scripts/python/bin/net_dropmonitor-record b/tools/perf/scripts/python/bin/net_dropmonitor-record
new file mode 100755 (executable)
index 0000000..423fb81
--- /dev/null
+++ b/tools/perf/scripts/python/bin/net_dropmonitor-record
@@ -0,0 +1,2 @@
+#!/bin/bash
+perf record -e skb:kfree_skb $@

diff --git a/tools/perf/scripts/python/bin/net_dropmonitor-report b/tools/perf/scripts/python/bin/net_dropmonitor-report
new file mode 100755 (executable)
index 0000000..8d698f5
--- /dev/null
+++ b/tools/perf/scripts/python/bin/net_dropmonitor-report
@@ -0,0 +1,4 @@
+#!/bin/bash
+# description: display a table of dropped frames
+
+perf script -s "$PERF_EXEC_PATH"/scripts/python/net_dropmonitor.py $@

diff --git a/tools/perf/scripts/python/net_dropmonitor.py b/tools/perf/scripts/python/net_dropmonitor.py
new file mode 100755 (executable)
index 0000000..a4ffc95
--- /dev/null
+++ b/tools/perf/scripts/python/net_dropmonitor.py
@@ -0,0 +1,72 @@
+# Monitor the system for dropped packets and proudce a report of drop locations and counts
+
+import os
+import sys
+
+sys.path.append(os.environ['PERF_EXEC_PATH'] + \
+               '/scripts/python/Perf-Trace-Util/lib/Perf/Trace')
+
+from perf_trace_context import *
+from Core import *
+from Util import *
+
+drop_log = {}
+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.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)
+
+def print_drop_table():
+       print "%25s %25s %25s" % ("LOCATION", "OFFSET", "COUNT")
+       for i in drop_log.keys():
+               (sym, off) = get_sym(i)
+               if sym == None:
+                       sym = i
+               print "%25s %25s %25s" % (sym, off, drop_log[i])
+
+
+def trace_begin():
+       print "Starting trace (Ctrl-C to dump results)"
+
+def trace_end():
+       print "Gathering kallsyms data"
+       get_kallsyms_table()
+       print_drop_table()
+
+# called from perf, when it finds a correspoinding event
+def skb__kfree_skb(name, context, cpu, sec, nsec, pid, comm,
+                       skbaddr, protocol, location):
+       slocation = str(location)
+       try:
+               drop_log[slocation] = drop_log[slocation] + 1
+       except:
+               drop_log[slocation] = 1