1#!/usr/bin/env perl 2 3# Read two files produced by the stackusage script, and show the 4# delta between them. 5# 6# Currently, only shows changes for functions listed in both files. We 7# could add an option to show also functions which have vanished or 8# appeared (which would often be due to gcc making other inlining 9# decisions). 10# 11# Another possible option would be a minimum absolute value for the 12# delta. 13# 14# A third possibility is for sorting by delta, but that can be 15# achieved by piping to sort -k5,5g. 16 17sub read_stack_usage_file { 18 my %su; 19 my $f = shift; 20 open(my $fh, '<', $f) 21 or die "cannot open $f: $!"; 22 while (<$fh>) { 23 chomp; 24 my ($file, $func, $size, $type) = split; 25 # Old versions of gcc (at least 4.7) have an annoying quirk in 26 # that a (static) function whose name has been changed into 27 # for example ext4_find_unwritten_pgoff.isra.11 will show up 28 # in the .su file with a name of just "11". Since such a 29 # numeric suffix is likely to change across different 30 # commits/compilers/.configs or whatever else we're trying to 31 # tweak, we can't really track those functions, so we just 32 # silently skip them. 33 # 34 # Newer gcc (at least 5.0) report the full name, so again, 35 # since the suffix is likely to change, we strip it. 36 next if $func =~ m/^[0-9]+$/; 37 $func =~ s/\..*$//; 38 # Line numbers are likely to change; strip those. 39 $file =~ s/:[0-9]+$//; 40 $su{"${file}\t${func}"} = {size => $size, type => $type}; 41 } 42 close($fh); 43 return \%su; 44} 45 46@ARGV == 2 47 or die "usage: $0 <old> <new>"; 48 49my $old = read_stack_usage_file($ARGV[0]); 50my $new = read_stack_usage_file($ARGV[1]); 51my @common = sort grep {exists $new->{$_}} keys %$old; 52for (@common) { 53 my $x = $old->{$_}{size}; 54 my $y = $new->{$_}{size}; 55 my $delta = $y - $x; 56 if ($delta) { 57 printf "%s\t%d\t%d\t%+d\n", $_, $x, $y, $delta; 58 } 59} 60