The documentation of lzo 'http://www.oberhumer.com/opensource/lzo/lzofaq.php' and lzo source code 'examples/precomp.c and examples/precomp2.c' Instructs library users that want to create pre-compressed data to make a call to lzo1x_optimize(..) after calling lzo1x_999_compress(..) to further optimize the compressed data for speed.
I consider a squashfs filesystem pre-compressed data (write once read many times)
Cost: slightly more time for compression (with identical compressed size) (The compression time increase in extremely marginal against the time lzo1x_999_compress(..) takes)
Gain: slightly less time for decompression (without any compressed size difference)