The graphs are built from the data in times.txt.

The data in times.txt were gathered by running

	xtime -s xbwk xegrep xgawk xmawk xnfa xpcre \
		xperl xpython xruby xtcl >times.txt

on an idle AMD Athlon 64 2800+ running in 32-bit mode.

To time just one program:

	xtime -s xegrep

xbwk refers to /home/rsc/bin/bwk, which is a copy of
the ``one true awk'' from Brian Kernighan's web site,
compiled with gcc -O2.

xnfa (not included) can be generated by

	gcc -O2 -o xnfa nfa0.c

where nfa0.c is the NFA implementation that can be downloaded
from the web site.

Russ Cox
January 2007
http://swtch.com/~rsc/regexp/