Add a script to visualize the kernel boot process / time

When optimizing the kernel boot time, it's very valuable to visualize
what is going on at which time. In addition, with some of the initializing
going asynchronous soon, it's valuable to track/print which worker thread
is executing the initialization.

This patch adds a script to turn a dmesg into a SVG graph (that can be
shown with tools such as InkScape, Gimp or Firefox) and a small change
to the initcall code to print the PID of the thread calling the initcall
(so that the script can work out the parallelism).
Signed-off-by: NArjan van de Ven <arjan@linux.intel.com>

init/main.c

@@ -708,7 +708,7 @@ int do_one_initcall(initcall_t fn)
 	int result;
 
 	if (initcall_debug) {
-		printk("calling  %pF\n", fn);
+		printk("calling  %pF @ %i\n", fn, task_pid_nr(current));
 		t0 = ktime_get();
 	}
 

scripts/bootgraph.pl

+#!/usr/bin/perl
+
+# Copyright 2008, Intel Corporation
+#
+# This file is part of the Linux kernel
+#
+# This program file is free software; you can redistribute it and/or modify it
+# under the terms of the GNU General Public License as published by the
+# Free Software Foundation; version 2 of the License.
+#
+# This program is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+# for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program in a file named COPYING; if not, write to the
+# Free Software Foundation, Inc.,
+# 51 Franklin Street, Fifth Floor,
+# Boston, MA 02110-1301 USA
+#
+# Authors:
+# 	Arjan van de Ven <arjan@linux.intel.com>
+
+
+#
+# This script turns a dmesg output into a SVG graphic that shows which
+# functions take how much time. You can view SVG graphics with various
+# programs, including Inkscape, The Gimp and Firefox.
+#
+#
+# For this script to work, the kernel needs to be compiled with the
+# CONFIG_PRINTK_TIME configuration option enabled, and with
+# "initcall_debug" passed on the kernel command line.
+#
+# usage:
+# 	dmesg | perl scripts/bootgraph.pl > output.svg
+#
+
+my @rows;
+my %start, %end, %row;
+my $done = 0;
+my $rowcount = 0;
+my $maxtime = 0;
+my $count = 0;
+while (<>) {
+	my $line = $_;
+	if ($line =~ /([0-9\.]+)\] calling  ([a-zA-Z\_]+)\+/) {
+		my $func = $2;
+		if ($done == 0) {
+			$start{$func} = $1;
+		}
+		$row{$func} = 1;
+		if ($line =~ /\@ ([0-9]+)/) {
+			my $pid = $1;
+			if (!defined($rows[$pid])) {
+				$rowcount = $rowcount + 1;
+				$rows[$pid] = $rowcount;
+			}
+			$row{$func} = $rows[$pid];
+		}
+		$count = $count + 1;
+	}
+
+	if ($line =~ /([0-9\.]+)\] initcall ([a-zA-Z\_]+)\+.*returned/) {
+		if ($done == 0) {
+			$end{$2} = $1;
+			$maxtime = $1;
+		}
+	}
+	if ($line =~ /Write protecting the/) {
+		$done = 1;
+	}
+}
+
+if ($count == 0) {
+	print "No data found in the dmesg. Make sure CONFIG_PRINTK_TIME is enabled and\n";
+	print "that initcall_debug is passed on the kernel command line.\n\n";
+	print "Usage: \n";
+	print "      dmesg | perl scripts/bootgraph.pl > output.svg\n\n";
+	exit;
+}
+
+print "<?xml version=\"1.0\" standalone=\"no\"?> \n";
+print "<svg width=\"1000\" height=\"100%\" version=\"1.1\" xmlns=\"http://www.w3.org/2000/svg\">\n";
+
+my @styles;
+
+$styles[0] = "fill:rgb(0,0,255);fill-opacity:0.5;stroke-width:1;stroke:rgb(0,0,0)";
+$styles[1] = "fill:rgb(0,255,0);fill-opacity:0.5;stroke-width:1;stroke:rgb(0,0,0)";
+$styles[2] = "fill:rgb(255,0,20);fill-opacity:0.5;stroke-width:1;stroke:rgb(0,0,0)";
+$styles[3] = "fill:rgb(255,255,20);fill-opacity:0.5;stroke-width:1;stroke:rgb(0,0,0)";
+$styles[4] = "fill:rgb(255,0,255);fill-opacity:0.5;stroke-width:1;stroke:rgb(0,0,0)";
+$styles[5] = "fill:rgb(0,255,255);fill-opacity:0.5;stroke-width:1;stroke:rgb(0,0,0)";
+$styles[6] = "fill:rgb(0,128,255);fill-opacity:0.5;stroke-width:1;stroke:rgb(0,0,0)";
+$styles[7] = "fill:rgb(0,255,128);fill-opacity:0.5;stroke-width:1;stroke:rgb(0,0,0)";
+$styles[8] = "fill:rgb(255,0,128);fill-opacity:0.5;stroke-width:1;stroke:rgb(0,0,0)";
+$styles[9] = "fill:rgb(255,255,128);fill-opacity:0.5;stroke-width:1;stroke:rgb(0,0,0)";
+$styles[10] = "fill:rgb(255,128,255);fill-opacity:0.5;stroke-width:1;stroke:rgb(0,0,0)";
+$styles[11] = "fill:rgb(128,255,255);fill-opacity:0.5;stroke-width:1;stroke:rgb(0,0,0)";
+
+my $mult = 950.0 / $maxtime;
+my $threshold = 0.0500 / $maxtime;
+my $stylecounter = 0;
+while (($key,$value) = each %start) {
+	my $duration = $end{$key} - $start{$key};
+
+	if ($duration >= $threshold) {
+		my $s, $s2, $e, $y;
+		$s = $value * $mult;
+		$s2 = $s + 6;
+		$e = $end{$key} * $mult;
+		$w = $e - $s;
+
+		$y = $row{$key} * 150;
+		$y2 = $y + 4;
+
+		$style = $styles[$stylecounter];
+		$stylecounter = $stylecounter + 1;
+		if ($stylecounter > 11) {
+			$stylecounter = 0;
+		};
+
+		print "<rect x=\"$s\" width=\"$w\" y=\"$y\" height=\"145\" style=\"$style\"/>\n";
+		print "<text transform=\"translate($s2,$y2) rotate(90)\">$key</text>\n";
+	}
+}
+
+
+# print the time line on top
+my $time = 0.0;
+while ($time < $maxtime) {
+	my $s2 = $time * $mult;
+	print "<text transform=\"translate($s2,89) rotate(90)\">$time</text>\n";
+	$time = $time + 0.1;
+}
+
+print "</svg>\n";