[OLPC-devel] just verified: 2306 + olpc + linux kernel works.

[Marcelo Tosatti]

On Fri, May 26, 2006 at 01:03:57AM +0100, David Woodhouse wrote:
> On Thu, 2006-05-25 at 21:02 -0300, Marcelo Tosatti wrote:
> > Last time I tried lzma on vmlinux the advantage was _very_ significant
> > (> 20% increase in compression ratio over gzip). 
> 
> What if you 'split -b 4096 vmlinux' and then compress each of the
> resulting files?

vmlinux (single piece)

uncompressed		gzip 			lzma
1192316 		527722 (44%)		425172 (35%)

[root at dmt lzma]# /usr/bin/time gzip vmlinux
0.30user 0.00system 0:00.31elapsed 96%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+201minor)pagefaults 0swaps

[root at dmt lzma]# /usr/bin/time lzma e vmlinux vmlinux.lzma
4.74user 0.01system 0:05.07elapsed 93%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+4231minor)pagefaults 0swaps

Now splitting with -b 4096 really kills lzma gains:

[root at dmt lzma]# du -csh .
2.4M    .
2.4M    total

[root at dmt gzip]# du -csh .
2.3M    .
2.3M    total