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author | Rasmus Villemoes <linux@rasmusvillemoes.dk> | 2015-08-20 11:53:30 +0200 |
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committer | Michal Marek <mmarek@suse.com> | 2015-08-28 17:04:40 +0200 |
commit | 5bbb9f753afe213aebc8dba30c7e2dbb73616b79 (patch) | |
tree | 70fd497c25222ffd604de186925d02c8a8c12178 | |
parent | d523b255de60880304038006de5f93f2db612ad6 (diff) | |
download | linux-5bbb9f753afe213aebc8dba30c7e2dbb73616b79.tar.bz2 |
scripts: add stackdelta script
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>
-rwxr-xr-x | scripts/stackdelta | 59 |
1 files changed, 59 insertions, 0 deletions
diff --git a/scripts/stackdelta b/scripts/stackdelta new file mode 100755 index 000000000000..48eabf2f48f8 --- /dev/null +++ b/scripts/stackdelta @@ -0,0 +1,59 @@ +#!/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; + } +} |