Re: [RFC] LZO de/compression support - take 4

From: Nitin Gupta
Date: Mon May 28 2007 - 04:44:44 EST


On 5/28/07, Daniel Hazelton <dhazelton@xxxxxxxxx> 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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