blob: 44d2dfd6216fdb092b9a1dd221b9756b79b0fad5 [file] [log] [blame]
Kamil Rytarowskicb77f0d2017-05-07 23:25:26 +02001#!/usr/bin/env perl
Greg Kroah-Hartmanb2441312017-11-01 15:07:57 +01002# SPDX-License-Identifier: GPL-2.0
Rasmus Villemoes5bbb9f72015-08-20 11:53:30 +02003
4# Read two files produced by the stackusage script, and show the
5# delta between them.
6#
7# Currently, only shows changes for functions listed in both files. We
8# could add an option to show also functions which have vanished or
9# appeared (which would often be due to gcc making other inlining
10# decisions).
11#
12# Another possible option would be a minimum absolute value for the
13# delta.
14#
15# A third possibility is for sorting by delta, but that can be
16# achieved by piping to sort -k5,5g.
17
18sub read_stack_usage_file {
19 my %su;
20 my $f = shift;
21 open(my $fh, '<', $f)
22 or die "cannot open $f: $!";
23 while (<$fh>) {
24 chomp;
25 my ($file, $func, $size, $type) = split;
26 # Old versions of gcc (at least 4.7) have an annoying quirk in
27 # that a (static) function whose name has been changed into
28 # for example ext4_find_unwritten_pgoff.isra.11 will show up
29 # in the .su file with a name of just "11". Since such a
30 # numeric suffix is likely to change across different
31 # commits/compilers/.configs or whatever else we're trying to
32 # tweak, we can't really track those functions, so we just
33 # silently skip them.
34 #
35 # Newer gcc (at least 5.0) report the full name, so again,
36 # since the suffix is likely to change, we strip it.
37 next if $func =~ m/^[0-9]+$/;
38 $func =~ s/\..*$//;
39 # Line numbers are likely to change; strip those.
40 $file =~ s/:[0-9]+$//;
41 $su{"${file}\t${func}"} = {size => $size, type => $type};
42 }
43 close($fh);
44 return \%su;
45}
46
47@ARGV == 2
48 or die "usage: $0 <old> <new>";
49
50my $old = read_stack_usage_file($ARGV[0]);
51my $new = read_stack_usage_file($ARGV[1]);
52my @common = sort grep {exists $new->{$_}} keys %$old;
53for (@common) {
54 my $x = $old->{$_}{size};
55 my $y = $new->{$_}{size};
56 my $delta = $y - $x;
57 if ($delta) {
58 printf "%s\t%d\t%d\t%+d\n", $_, $x, $y, $delta;
59 }
60}