El jue, 15-08-2002 a las 00:24, James Davis escribió: > I'd be interested in what people think of my work so far, it compiles > without problem as far as I know under Cygwin, Linux and OpenBSD. It's > available at http://users.ox.ac.uk/~spet1067/bfsum/ and is far from > polished at the moment. It's slow (although I have improved this), > lacks the -c option of md5sum, ignores the binary/text options and the > code is quite messy. For those who try it, I apologise for filename that > results from compilation but I've been using the same Makefile in windows. Yep, compiles and works fine on Adelita, Debian Testing with gcc 2.95.4. As for time-consuming matters, bfsumming a 120-meg file took more than 10 minutes (I stopped the process) in an AthlonXP/1700+ (rather big machine, some 700-meg DDR RAM and not too much sys load). Let's try with something smaller... 47 KB text file: real 0m2.569s user 0m0.910s sys 0m0.020s 1 MB of random stuff (dd if=/dev/urandom of=shit bs=1M count=1): real 0m56.729s user 0m20.680s sys 0m0.400s Now let's try optimization of the executable: we'll put this in the CFLAGS var of the Makefile: CFLAGS=-O3 -funroll-all-loops -march=i586 Oops, I failed!! It was slower: real 1m19.000s user 0m27.920s sys 0m0.660s Now try gcc 3.0.4 with -funroll-all-loops and -march=athlon: real 0m48.296s user 0m16.910s sys 0m0.290s Little better. But I expected even better results. Try -funroll-all-loops in any PentiumIV, it should boost performance up (for a past experience similar to this, I concluded that this flag improved performance in Intel processors much more than it did in AMD's). Well, hope this info is useful. Regards! Pope > > James > > -- > James Davis \ james.davis@st-peters.ox.ac.uk > St. Peter's College \ > PGP Key ID : 0x7E1F718A \ http://users.ox.ac.uk/~spet1067/ > > > ----------------------------------------------------------------- > This list is provided by the SecurityFocus ARIS analyzer service. > For more information on this free incident handling, management > and tracking system please see: http://aris.securityfocus.com > > -- Luis Gómez Miralles InfoEmergencias - Technical Department Phone (+34) 654 24 01 34 Fax (+34) 963 49 31 80 lgomezat_private PGP Public Key available at http://www.infoemergencias.com/lgomez.asc ----------------------------------------------------------------- This list is provided by the SecurityFocus ARIS analyzer service. For more information on this free incident handling, management and tracking system please see: http://aris.securityfocus.com
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