Re: [RFC PATCH v2 0/4] Add support for LZ4-compressed kernel

Peter Korsgaard
2013-02-26T21:58:11Z

>>>>> "Nicolas" == Nicolas Pitre <nico@fluxnic.net> writes:

Hi,

>> Did you actually *try* the new LZO version and the patch (which is attached
>> once again) as explained in https://lkml.org/lkml/2013/2/3/367 ?
>>
>> Because the new LZO version is faster than LZ4 in my testing, at least
>> when comparing apples with apples and enabling unaligned access in
>> BOTH versions:
>>
>> armv7 (Cortex-A9), Linaro gcc-4.6 -O3, Silesia test corpus, 256 kB block-size:
>>
>> compression speed decompression speed
>>
>> LZO-2012 : 44 MB/sec 117 MB/sec no unaligned access
>> LZO-2013-UA : 47 MB/sec 167 MB/sec Unaligned Access
>> LZ4 r88 UA : 46 MB/sec 154 MB/sec Unaligned Access

Nicolas> To be fair, you should also take into account the compressed
Nicolas> size of a typical ARM kernel. Sometimes a slightly slower
Nicolas> decompressor may be faster overall if the compressed image to
Nicolas> work on is smaller.

Yes, but notice that lzo compressed BETTER than lz4 - E.G. from the
introduction mail:

1. ARMv7, 1.5GHz based board
Kernel: linux 3.4
Uncompressed Kernel Size: 14MB
Compressed Size Decompression Speed
LZO 6.7MB 21.1MB/s
LZ4 7.3MB 29.1MB/s, 45.6MB/s(UA)

--
Bye, Peter Korsgaard