Re: gzip vs. bzip2 (mainly de-)compression "benchmark"

From: Mark Mielke (mark@mark.mielke.cc)
Date: Mon May 06 2002 - 20:58:48 EST

I don't think it is fair to measure compression speed of a relatively
small image, such as the kernel image, to the compression of your
entire root partition. There are certain file formats that are more
difficult for bzip2 to deal with, than others.

The kernel image itself will not take 10 minutes to decompress with
bzip2. For floppy disks, it is doubtful that the image could be read
off the floppy faster than even older computers could un-bzip2 the
images, meaning that execution time is irrelevant in this context.

mark

On Mon, May 06, 2002 at 11:58:42AM -0600, Thunder from the hill wrote:
> Hi,
>
> gzipping, bzip2ing a solaris disk image from my old sparc64 under alpha
> (approx. 2 GiB) and relative load.
> This has been done for testing purposes for those fiddling around with the
> kernel compression algorithms.
>
> # ls -l ; ls -lh
> -rw-r--r-- 1 root root 2164082688 May 5 04:41 old-root
> -rw-r--r-- 1 root root 2.0G May 5 04:41 old-root
>
> # time gzip -9n old-root
> 9035.15user 119.40system 11:38:12elapsed 21%CPU
> (0avgtext+0avgdata 0maxresident)k
> 0inputs+0outputs (166major+112minor)pagefaults 0swaps
>
> # ls -l ; ls -lh
> -rw-r--r-- 1 65534 65534 546148165 May 2 11:30 old-root.gz
> -rw-r--r-- 1 65534 65534 521M May 2 11:30 old-root.gz
>
> # time gzip -cd old-root.gz > /dev/null
> 134.11user 66.22system 10:42.91elapsed 31%CPU
> (0avgtext+0avgdata 0maxresident)k
> 0inputs+0outputs (102major+37minor)pagefaults 0swaps
>
> # time bzip2 -9z old-root
> (Unfortunately crashed shortly after completion when I modprobed khttpd and
> tried to make a connection. I can redo that if you are interested in the
> results, but I tell you it took some time... user was in the 11,000 I
> remember.)
>
> # ls -l ; ls -lh
> -rw-r--r-- 1 root root 496780930 May 5 04:41 old-root.bz2
> -rw-r--r-- 1 root root 474M May 5 04:41 old-root.bz2
>
> # time bzip2 -cdk old-root.bz2 > /dev/null
> 1010.44user 33.15system 58:12.14elapsed 29%CPU
> (0avgtext+0avgdata 0maxresident)k
> 0inputs+0outputs (117major+914minor)pagefaults 0swaps
>
> Penguin: Linux 2.4.8 (didn't have time to compile the latest here) on an
> Alpha 300, 384 MiB RAM. Meanwhile someone was compiling Redhat
> Package Manager v4.1, later the Linux Kernel v2.4 repository.
>
> Regards,
> Thunder
> --
> if (errno == ENOTAVAIL)
> fprintf(stderr, "Error: Talking to Microsoft server!\n");
>
> -
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-- 
mark@mielke.cc/markm@ncf.ca/markm@nortelnetworks.com __________________________
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                       and in the darkness bind them...

                           http://mark.mielke.cc/

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