Re: [PATCH] init: bzip2 or lzma -compressed kernels and initrds
From: Bill Davidsen
Date: Mon Sep 15 2008 - 13:15:19 EST
Frans Meulenbroeks wrote:
2008/9/15 Rob Landley <rob@xxxxxxxxxxx>:
On Sunday 07 September 2008 00:48:31 Willy Tarreau wrote:
Hi Alain,
+config KERNEL_LZMA
+ bool "LZMA"
+ help
+ The most recent compression algorithm.
+ Its ratio is best, decompression speed is between the other
+ 2. Compression is slowest.
+ The kernel size is about 33 per cent smaller with lzma,
+ in comparison to gzip.
isn't memory usage in the same range as bzip2 ?
Last I checked it was more. (I very vaguely recall somebody saying 16 megs
working space back when this was first submitted to busybox, but that was a
few years ago...)
A quick Google found a page that benchmarks them. Apparently it depends
heavily on which compression option you use:
http://tukaani.org/lzma/benchmarks
[...]
Apologies if I'm sidetracking the discussion, but I'd like to coin a remark.
For kernel/ramfsimage etc the best choice is the one that has the
fastest decompression (info on tukaani.org says gzip).
Rationale: as it uncompresses faster the system will boot faster.
Of course this only holds if the background memory can hold that
image. For disk based systems, I assume this is not a problem at all,
but for embedded systems with all software in flash a higher
compression ration (e.g. lzma) can just make the difference between
fit and not fit (so in those cases lzma could just make your day).
Given the larger memory needed to decompress, it becomes a very interesting
calculation in really small memory machines.
--
Bill Davidsen <davidsen@xxxxxxx>
"We have more to fear from the bungling of the incompetent than from
the machinations of the wicked." - from Slashdot
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