m1rc3/norruption/2/plot-corr: make scatter plot of time between corruptions

With simulation (-s). Also updated the Makefile and renamed the previous
"corr"(uption) to "dump", to free it for "correlation".

m1rc3/norruption/2/plot-corr

@@ -0,0 +1,75 @@
+#!/usr/bin/perl
+
+sub usage
+{
+	print STDERR "usage: $0 [-s] [log_file]\n";
+	exit(1);
+}
+
+
+if ($ARGV[0] eq "-s") {
+	shift @ARGV;
+	$sim = 1;
+}
+&usage if $ARGV[0] =~ /^-/;
+
+$n = 1;
+while (<>) {
+	next unless /^=== (\d+) ===/;
+	while ($1 != $n) {
+		push(@f, $n);
+		$n++;
+	}
+	$n++;
+}
+
+$n--;
+$t = int($n/@f+0.5);
+
+$last = 0;
+for (@f) {
+	push(@d, $_-$last);
+	$last = $_;
+}
+
+if ($sim) {
+	# y = 1-exp(-x/T)
+	# 1-y = exp(-x/T)
+	# ln(1-y) = -x/T
+	# -T*ln(1-y) = x
+
+	$type = " (SIMULATED)";
+	@d = ();
+	for ($i = 0; $i != @f; $i++) {
+		push(@d, -$t*log(1-rand));
+	}
+}
+
+for (@d) {
+	$max = $_ if $_ > $max;
+}
+
+$cmd = "|gnuplot -e '".
+    'set term postscript color eps enhanced solid lw 2 20;'.
+    'set output "out.eps";'.
+    'set xrange [0:'.$max*1.05.'];'.
+    'set yrange [0:'.$max*1.05.'];'.
+    'set title "Correlation of time to adjacent corruptions'.$type.'";'.
+    'set xlabel "Cycles since previous event";'.
+    'set ylabel "Cycles until next event";'.
+    'plot "-" with points pt 7 notitle'.
+    "'";
+
+open(PIPE, $cmd) || die "open: $!";
+undef $last;
+for (@d) {
+	print PIPE "$last $_\n" if defined $last;
+	$last = $_;
+}
+close(PIPE) || die "close: $!";
+
+system("cat out.eps | ".
+    "gs -sDEVICE=ppmraw -r100 -sOutputFile=- ".
+    "-dTextAlphaBits=4 -dGraphicsAlphaBits=4 -sPAPERSIZE=a4 -q - | ".
+    "convert -trim - out.png");
+unlink("out.eps");