Date: Mon, 16 Dec 1996 10:00:09 +0200 (EET) From: Heikki Suonsivu <hsu@clinet.fi> To: David Muir Sharnoff <muir@idiom.com> Cc: freebsd-bugs@freebsd.org Subject: Re: Re: bin/146 Message-ID: <199612160800.KAA03485@cantina.clinet.fi> In-Reply-To: David Muir Sharnoff's message of 16 Dec 1996 03:52:30 %2B0200 References: <199612160141.RAA10917@idiom.com>
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In article <199612160141.RAA10917@idiom.com> David Muir Sharnoff <muir@idiom.com> writes:
* Synopsis: version of compress is kinda old and slow
Until gzip is faster than compress, there is still a use
for compress. ncompress-4.2.4 is faster than gzip. Not
by much anymore, but still a bit faster.
gzip is by default doing best compression ratio, not best speed. Compress
performance and memory use can be tuned also, using -b option, but
compression performance drops dramatically while gzip options do not make
that much a difference (gzip -1 still compresses better than compress at
its best, and result is half of what compress -b12 makes!):
time ratio decompress
ncompress 4.2.4 -b12 6.80+1.06 60.4% 3.68+1.27
gzip -1 10.49+0.68 31.4% 3.46+0.21
ncompress 4.2.4 13.01+1.48 46.9% 4.12+1.11
/usr/bin/compress 18.45+0.89 43.6% 6.68+0.31
gzip 27.98+0.65 26.8% 3.25+0.18
Most results are from /usr/bin/time, it seems that the test was a bit too
short as time vary. Curiously freebsd compress produced a smaller file
than never compress ?
As long as someone is going to be done with the resulting files, like
transferring them through something slower than ethernet the extra
compression time will be saved in transfer time (and money, often!)
compress is to my knowledge patent-hampered, so it also would not serve all
the audience listening.
For people who need the best compression speed I would rather suggest gzip
-1. I cannot really see why anyone would want to use slightly faster
compress when compression result is that much worse ?
hsu@zetor.clinet.fi Mon 50: date ; ./compress < /kernel | wc -c ; date
Mon Dec 16 08:46:01 EET 1996
4592777
real 0:16.59; user 13.014; system 1.475; cpu 87.2%; swaps 0;
disk reads 116; disk writes 1; average size 1187; max size 542
Mon Dec 16 08:46:17 EET 1996
hsu@zetor.clinet.fi Mon 51: date ; /usr/bin/compress < /kernel | wc -c ; date
Mon Dec 16 08:46:27 EET 1996
4270573
real 0:21.20; user 18.454; system 0.894; cpu 91.2%; swaps 0;
disk reads 0; disk writes 1; average size 746; max size 482
Mon Dec 16 08:46:48 EET 1996
hsu@zetor.clinet.fi Mon 52: date ; gzip -1 < /kernel | wc -c ; dateMon Dec 16 08:47:00 EET 1996
3068781
real 0:12.60; user 10.485; system 0.683; cpu 88.5%; swaps 0;
disk reads 0; disk writes 1; average size 722; max size 390
Mon Dec 16 08:47:13 EET 1996
hsu@zetor.clinet.fi Mon 53: date ; gzip < /kernel | wc -c ; date
Mon Dec 16 08:47:17 EET 1996
2620417
real 0:31.59; user 27.979; system 0.645; cpu 90.5%; swaps 0;
disk reads 0; disk writes 0; average size 727; max size 262
Mon Dec 16 08:47:49 EET 1996
hsu@zetor.clinet.fi Mon 54:
-Dave
--
Heikki Suonsivu, T{ysikuu 10 C 83/02210 Espoo/FINLAND, hsu@clinet.fi
mobile +358-40-5519679 work +358-9-43542270 fax -4555276
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