Is Unix stdio slow?

Dominic Dunlop domo at riddle.UUCP
Wed Oct 12 00:16:48 AEST 1988


Those interested in the speed of stdio may care to follow up this
reference:

Grep Wars
Andrew Hume
AT&T Bell Laboratories, Murray Hill, New Jersey 07974
Published in proceedings of European UNIX Systems User Group spring 1988
	conference, ISBN 0 9513181 0 1 (available at pounds 20 + pounds 6.08
	surface mail or pounds 22.63 airmail from EUUG, Owles Hall,
	Buntingford, Herts SG9 9PL, England; phone +44 763 73039 -- Visa
	cards accepted)

Abstract:
	Subsequent to the sixth edition of the UNIX operating system there
	have been different versions of the searching tool grep using
	different algorithms tuned for different types of search patterns.
	Friendly competition between the tools has yielded a succession of
	performance enhancements.

	We describe the latest round of improvements, based on the fio fast
	I/O library and incorporating the Boyer-Moore algorithm.  Although
	grep is now 3-4 times faster than it was, egrep is typically 8-10
	(for some common patterns 30-40) times faster than the new grep.

I believe that a similar paper has been presented at Usenix, possibly at
the summer 1987 conference, but I'm afraid I don't have the proceedings to
hand.

At the EUUG conference, Andrew said (as I recall) that he'd like to see
fio hit the public domain, but that whether it did or not was a matter
which was out of his hands.  It was also not clear whether fio would ever
be incorporated into a licensed release of the UNIX operating system,
either as a set of library functions, or even merely as a part of
[ef]*grep.
-- 
Dominic Dunlop
domo at sphinx.co.uk  domo at riddle.uucp



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