speed of bzip2 versus gzip
list at museum.rain.com
Sat Jul 21 01:24:56 UTC 2007
On Fri, Jul 20, 2007 at 05:50:20PM -0700, Chuck Swiger wrote:
> On Jul 20, 2007, at 5:37 PM, Norberto Meijome wrote:
>>> Is it normal for bzip2 to be significantly slower than gzip?
>>> If not, where can I look for things that might be causing
>>> "bzip2 --fast" to take 50-60 times longer to compress a
>>> (sendmail log) file than gzip?
>> i never measured it to see if it is 50-60 times slower, but yes, gzip
>> bzip2 out of the water on speed. I wanted to use bzip2 to compress
>> weblog files, but gzip beat it my miles, and bzip2 wasn't THAT much better
>> compressing it to make it worth it.
> Thanks for the feedback, Norberto.
> Of course, it all depends on what your priorities are, too-- if what you
> want is a final tarball which is being mirrored and downloaded frequently,
> then your goal is to obtain the absolute best compression, and how much CPU
> --best takes isn't important.
> Comparing the default (-5 compression?) of gzip to bzip2 would probably be
> more reasonable if you care about reasonably timely compression.
If I read the man page correctly, bzip2 defaults to --best, which is why
I compared gzip to bzip2 --fast. With the 1.5G sendmail log, bzip2 --fast
compresses to just under 10M in about 55 minutes, give or take. bzip2
--best compresses 1.5G to 1.8M, but takes about 2.25 hours. gzip
compresses almost as well (with 3% or so) as --fast, but does it in 1
minute instead of 55 on a dual P-III 1.4GHz (but of course, using only
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