Basic memory profiling setup.

This makes it a bit easier to profile memory usage of certain components and
plot them using Gnuplot. In the past I would write one-off scripts for this and
throw them away, only to figure out I needed them again later on.

Profiling samples are written to profile/samples and can be plotted using
corresponding Gnuplot scripts found in profile/plot. The latter requires
Gnuplot to be installed.

profile/plot/lexer/big_xml.gnuplot

@@ -0,0 +1,20 @@
+#!/usr/bin/env gnuplot
+
+set title "Lexing 10MB of XML"
+
+set xlabel "Sample"
+set ylabel "Memory (MB)"
+
+set yrange [0:*]
+
+set term qt persist
+set grid
+
+set style line 1 lc rgb "#0060ad" lt 1 lw 2 pt 7 ps 1
+
+plot "profile/samples/lexer/big_xml.txt" \
+    using 0:($1 / 1024 ** 2) \
+    with linespoints ls 1 \
+    title "Memory"
+
+# vim: set ft=gnuplot: