Re: [PATCH] init: bzip2 or lzma -compressed kernels and initrds

[Bill Davidsen <davidsen@tmr.com>]

Frans Meulenbroeks wrote:
> 2008/9/15 Rob Landley <rob@landley.net>:
>> 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@tmr.com>
   "We have more to fear from the bungling of the incompetent than from
the machinations of the wicked."  - from Slashdot