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

[Peter Korsgaard]

>>>>> "Nicolas" == Nicolas Pitre <nico@xxxxxxxxxxx> 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
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