[RFC PATCH v0 0/3] erofs-utils: support multiple block compression

[Gao Xiang]

On Wed, Dec 30, 2020 at 04:47:25PM +0800, Gao Xiang via Linux-erofs wrote:
> From: Gao Xiang <hsiangkao at aol.com>
> 
> Hi folks,
> 
> This is the first RFC patch of multiple block compression (including
> erofsfuse) after I carefully think over the on-disk design to support
> multiblock in-place decompression.
> 
> Compression ratio results (POC, lz4hc, lz4-1.9.3, not final result):
> 	1000000000		enwik9
> 		621211648	enwik9_4k.squashfs.img
> 	 557858816      	enwik9_4k.erofs.img
> 		556191744	enwik9_8k.squashfs.img
> 		502661120	enwik9_16k.squashfs.img
> 	 500723712		enwik9_8k.erofs.img
> 		458784768	enwik9_32k.squashfs.img
> 	 453971968		enwik9_16k.erofs.img
> 		422318080	enwik9_64k.squashfs.img
> 	 416686080		enwik9_32k.erofs.img
> 		398204928	enwik9_128k.squashfs.img
> 	 395276288		enwik9_64k.erofs.img

I can also think out several compress strategies to control read amplification
but maintain a given C/R due to EROFS can compress variable-sized input data
to arbitary compressed block count for each pcluster, FYI.

Thanks,
Gao Xiang