mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-11-01 17:08:10 +00:00
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>
59 lines
1.8 KiB
Perl
Executable file
59 lines
1.8 KiB
Perl
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 <old> <new>";
|
|
|
|
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;
|
|
}
|
|
}
|