From c94b6ac50f59e49cd080c76a07ea2734798da37d Mon Sep 17 00:00:00 2001
From: Christian Couder <christian.couder@gmail.com>
Date: Mon, 26 Mar 2018 09:24:30 +0200
Subject: [PATCH 1/2] perf/aggregate: add display_dir()

This new helper function will be reused in a subsequent
commit.

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 t/perf/aggregate.perl | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/t/perf/aggregate.perl b/t/perf/aggregate.perl
index 821cf1498b..890d85fa7b 100755
--- a/t/perf/aggregate.perl
+++ b/t/perf/aggregate.perl
@@ -147,6 +147,11 @@ sub have_slash {
 	return 0;
 }
 
+sub display_dir {
+	my ($d) = @_;
+	return exists $dirabbrevs{$d} ? $dirabbrevs{$d} : $dirnames{$d};
+}
+
 sub print_default_results {
 	my %descrs;
 	my $descrlen = 4; # "Test"
@@ -168,8 +173,7 @@ sub print_default_results {
 	my %times;
 	my @colwidth = ((0)x@dirs);
 	for my $i (0..$#dirs) {
-		my $d = $dirs[$i];
-		my $w = length (exists $dirabbrevs{$d} ? $dirabbrevs{$d} : $dirnames{$d});
+		my $w = length display_dir($dirs[$i]);
 		$colwidth[$i] = $w if $w > $colwidth[$i];
 	}
 	for my $t (@subtests) {
@@ -188,8 +192,7 @@ sub print_default_results {
 
 	printf "%-${descrlen}s", "Test";
 	for my $i (0..$#dirs) {
-		my $d = $dirs[$i];
-		printf "   %-$colwidth[$i]s", (exists $dirabbrevs{$d} ? $dirabbrevs{$d} : $dirnames{$d});
+		printf "   %-$colwidth[$i]s", display_dir($dirs[$i]);
 	}
 	print "\n";
 	print "-"x$totalwidth, "\n";

From 2e3efd0613cdff393f8c75be77bca9751915ea28 Mon Sep 17 00:00:00 2001
From: Christian Couder <christian.couder@gmail.com>
Date: Mon, 26 Mar 2018 09:24:31 +0200
Subject: [PATCH 2/2] perf/aggregate: add --sort-by=regression option

One of the most interesting thing one can be interested in when
looking at performance test results is possible performance
regressions.

This new option makes it easy to spot such possible regressions.

This new option is named '--sort-by=regression' to make it
possible and easy to add other ways to sort the results, like for
example '--sort-by=utime'.

If we would like to sort according to how much the stime regressed
we could also add a new option called '--sort-by=regression:stime'.
Then '--sort-by=regression' could become a synonym for
'--sort-by=regression:rtime'.

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 t/perf/aggregate.perl | 59 ++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 58 insertions(+), 1 deletion(-)

diff --git a/t/perf/aggregate.perl b/t/perf/aggregate.perl
index 890d85fa7b..48637ef64b 100755
--- a/t/perf/aggregate.perl
+++ b/t/perf/aggregate.perl
@@ -37,7 +37,7 @@ sub format_times {
 }
 
 my (@dirs, %dirnames, %dirabbrevs, %prefixes, @tests,
-    $codespeed, $subsection, $reponame);
+    $codespeed, $sortby, $subsection, $reponame);
 while (scalar @ARGV) {
 	my $arg = $ARGV[0];
 	my $dir;
@@ -46,6 +46,18 @@ while (scalar @ARGV) {
 		shift @ARGV;
 		next;
 	}
+	if ($arg =~ /--sort-by(?:=(.*))?/) {
+		shift @ARGV;
+		if (defined $1) {
+			$sortby = $1;
+		} else {
+			$sortby = shift @ARGV;
+			if (! defined $sortby) {
+				die "'--sort-by' requires an argument";
+			}
+		}
+		next;
+	}
 	if ($arg eq "--subsection") {
 		shift @ARGV;
 		$subsection = $ARGV[0];
@@ -209,6 +221,49 @@ sub print_default_results {
 	}
 }
 
+sub print_sorted_results {
+	my ($sortby) = @_;
+
+	if ($sortby ne "regression") {
+		die "only 'regression' is supported as '--sort-by' argument";
+	}
+
+	my @evolutions;
+	for my $t (@subtests) {
+		my ($prevr, $prevu, $prevs, $prevrev);
+		for my $i (0..$#dirs) {
+			my $d = $dirs[$i];
+			my ($r, $u, $s) = get_times("$resultsdir/$prefixes{$d}$t.times");
+			if ($i > 0 and defined $r and defined $prevr and $prevr > 0) {
+				my $percent = 100.0 * ($r - $prevr) / $prevr;
+				push @evolutions, { "percent"  => $percent,
+						    "test"     => $t,
+						    "prevrev"  => $prevrev,
+						    "rev"      => $d,
+						    "prevr"    => $prevr,
+						    "r"        => $r,
+						    "prevu"    => $prevu,
+						    "u"        => $u,
+						    "prevs"    => $prevs,
+						    "s"        => $s};
+			}
+			($prevr, $prevu, $prevs, $prevrev) = ($r, $u, $s, $d);
+		}
+	}
+
+	my @sorted_evolutions = sort { $b->{percent} <=> $a->{percent} } @evolutions;
+
+	for my $e (@sorted_evolutions) {
+		printf "%+.1f%%", $e->{percent};
+		print " " . $e->{test};
+		print " " . format_times($e->{prevr}, $e->{prevu}, $e->{prevs});
+		print " " . format_times($e->{r}, $e->{u}, $e->{s});
+		print " " . display_dir($e->{prevrev});
+		print " " . display_dir($e->{rev});
+		print "\n";
+	}
+}
+
 sub print_codespeed_results {
 	my ($subsection) = @_;
 
@@ -263,6 +318,8 @@ binmode STDOUT, ":utf8" or die "PANIC on binmode: $!";
 
 if ($codespeed) {
 	print_codespeed_results($subsection);
+} elsif (defined $sortby) {
+	print_sorted_results($sortby);
 } else {
 	print_default_results();
 }