linux_kernel/scripts/bloat-o-meter

#!/usr/bin/python
#
# Copyright 2004 Matt Mackall <mpm@selenic.com>
#
# inspired by perl Bloat-O-Meter (c) 1997 by Andi Kleen
#
# This software may be used and distributed according to the terms
# of the GNU General Public License, incorporated herein by reference.

import sys, os, re

if len(sys.argv) != 3:
    sys.stderr.write("usage: %s file1 file2\n" % sys.argv[0])
    sys.exit(-1)

def getsizes(file):
    sym = {}
    for l in os.popen("nm --size-sort " + file).readlines():
        size, type, name = l[:-1].split()
        if type in "tTdDbBrR":
            # strip generated symbols
            if name.startswith("__mod_"): continue
            if name.startswith("SyS_"): continue
            if name.startswith("compat_SyS_"): continue
            if name == "linux_banner": continue
            # statics and some other optimizations adds random .NUMBER
            name = re.sub(r'\.[0-9]+', '', name)
            sym[name] = sym.get(name, 0) + int(size, 16)
    return sym

old = getsizes(sys.argv[1])
new = getsizes(sys.argv[2])
grow, shrink, add, remove, up, down = 0, 0, 0, 0, 0, 0
delta, common = [], {}
otot, ntot = 0, 0

for a in old:
    if a in new:
        common[a] = 1

for name in old:
    otot += old[name]
    if name not in common:
        remove += 1
        down += old[name]
        delta.append((-old[name], name))

for name in new:
    ntot += new[name]
    if name not in common:
        add += 1
        up += new[name]
        delta.append((new[name], name))

for name in common:
        d = new.get(name, 0) - old.get(name, 0)
        if d>0: grow, up = grow+1, up+d
        if d<0: shrink, down = shrink+1, down-d
        delta.append((d, name))

delta.sort()
delta.reverse()

print("add/remove: %s/%s grow/shrink: %s/%s up/down: %s/%s (%s)" % \
      (add, remove, grow, shrink, up, -down, up-down))
print("%-40s %7s %7s %+7s" % ("function", "old", "new", "delta"))
for d, n in delta:
    if d: print("%-40s %7s %7s %+7d" % (n, old.get(n,"-"), new.get(n,"-"), d))

print("Total: Before=%d, After=%d, chg %+.2f%%" % \
    (otot, ntot, (ntot - otot)*100.0/otot))