5bbb9f753a
This adds a simple perl script for reading two files as produced by
the stackusage script and computing the changes in stack usage. For
example:
$ scripts/stackusage -o /tmp/old.su CC=gcc-4.7 -j8 fs/ext4/
$ scripts/stackusage -o /tmp/new.su CC=gcc-5.0 -j8 fs/ext4/
$ scripts/stackdelta /tmp/{old,new}.su | sort -k5,5g
shows that gcc 5.0 generally produces less stack-hungry code than gcc
4.7. Obviously, the script can also be used for measuring the effect
of commits, .config tweaks or whatnot.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Michal Marek <mmarek@suse.com>
1.8 KiB
Executable File
#!/usr/bin/perl
Read two files produced by the stackusage script, and show the
delta between them.
Currently, only shows changes for functions listed in both files. We
could add an option to show also functions which have vanished or
appeared (which would often be due to gcc making other inlining
decisions).
Another possible option would be a minimum absolute value for the
delta.
A third possibility is for sorting by delta, but that can be
achieved by piping to sort -k5,5g.
sub read_stack_usage_file {
my %su;
my $f = shift;
open(my $fh, '<', $f)
or die "cannot open f: !";
while (<$fh>) {
chomp;
my ($file, $func, $size, $type) = split;
# Old versions of gcc (at least 4.7) have an annoying quirk in
# that a (static) function whose name has been changed into
# for example ext4_find_unwritten_pgoff.isra.11 will show up
# in the .su file with a name of just "11". Since such a
# numeric suffix is likely to change across different
# commits/compilers/.configs or whatever else we're trying to
# tweak, we can't really track those functions, so we just
# silently skip them.
#
# Newer gcc (at least 5.0) report the full name, so again,
# since the suffix is likely to change, we strip it.
next if $func =~ m/^[0-9]+$/;
$func =~ s/..*$//;
# Line numbers are likely to change; strip those.
$file =~ s/:[0-9]+$//;
$su{"${file}\t${func}"} = {size => $size, type => $type};
}
close($fh);
return %su;
}
@ARGV == 2 or die "usage: $0 ";
my $old = read_stack_usage_file($ARGV[0]); my $new = read_stack_usage_file($ARGV[1]); my @common = sort grep {exists $new->{$}} keys %$old; for (@common) { my $x = $old->{$}{size}; my $y = $new->{$}{size}; my $delta = $y - $x; if ($delta) { printf "%s\t%d\t%d\t%+d\n", $, $x, $y, $delta; } }