[linux-mm-cc] [RFC] LZO de/compression support - take 4

Nitin Gupta nitingupta910 at gmail.com
Mon May 28 04:37:04 EDT 2007


On 5/28/07, Daniel Hazelton <dhazelton at enter.net> wrote:
> Test code for this version (take 4) of the minimized LZO1X (from the liblzo
> v2) is complete.
>
>
> I don't see a significant slow-down comparing the complete liblzo2 to this
> minimized code on my system (Pentium M 1.73GHz, 1GB Ram, Kubuntu Feisty
> (stock Kubuntu kernel)). Rather, I see the opposite. This *might* have been
> caused by the dynamic linking (or similar) so rather than rely on simply
> doing "time xxx" I actually put checks around the calls to the
> compress/decompress functions themselves.
>
> ('Tiny LZO' is what I call Nitins extremely small implementation of
> lzo1x_[de]compress)
>
> Output of the provided "test" script:
> 10 run averages:
> 'Tiny LZO':
>         Combined: 113.2 usec
>         Compression: 77.4 usec
>         Decompression: 35.8 usec
> 'liblzo2':
>         Combined: 140.7 usec
>         Compression: 94 usec
>         Decompression: 46.7 usec
>
> (The "Combined" average is the average time taken for a compress+decompress)
>
> TODO:
> -Implement userspace version of likely/unlikely
> -Implement cpu_to_le16 so code functions on BE systems
>
> DRH
>
>

As you mentioned in your mail, you are using lzo1x_1_11_compress()
which is slower than what I ported (which is same as what is exported
by miniLZO). So, can you please test with the version ported  - this
is found in lzo/src/lzo1x_1.c (or in minilzo.c).
Also, can you please use 'take 5' for your next testing?

Thanks,
Nitin


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