[arch-general] mkinitcpio compression

[Dimitrios Apostolou]

On Sun, 27 Feb 2011, Thomas Bächler wrote:
> Am 27.02.2011 03:12, schrieb Dimitrios Apostolou:
>> Hello list,
>>
>> I'm using arch on an old laptop with only 128MB RAM. I had problems
>> compressing the initcpio image with lzma, it always failed allocating
>> memory. The following one-line patch allowed me to set my own
>> compression level in mkinitcpio.conf, with COMPRESSION="lzma -4"
>
> Does it also work if you simply omit any option and use the default? If
> you read the manpage, lzma -9 shouldn't be used anyway.

The default setting is -6 and it works, but I prefer -4 to avoid swapping. 
But what I'm arguing is that the default should be used anyway, and leave 
it to the user to choose a custom setting only if necessary.

FWIW compressing the kernel26-fallback image with various settings 
(no_options, -e, -4, -4e, -9, -9e) yields almost identical results, even 
if -9 needs many times the memory of -6. CPU times are all from 20 to 25 
seconds:


-rw-r--r-- 1 jimis jimis 10293248 Feb 27 15:19 kernel26-fallback.orig
-rw-r--r-- 1 jimis jimis  7860781 Feb 27 15:22 kernel26-fallback.4.lzma
-rw-r--r-- 1 jimis jimis  7849183 Feb 27 15:25 kernel26-fallback.4e.lzma
-rw-r--r-- 1 jimis jimis  7848882 Feb 27 15:26 kernel26-fallback.6e.lzma
-rw-r--r-- 1 jimis jimis  7848866 Feb 27 15:28 kernel26-fallback.9e.lzma
-rw-r--r-- 1 jimis jimis  7846985 Feb 27 15:22 kernel26-fallback.9.lzma
-rw-r--r-- 1 jimis jimis  7846962 Feb 27 15:21 kernel26-fallback.6.lzma


Dimitris