On 07/25/2017 03:29 PM, Peter Lieven wrote: >>> + deflate: Standard zlib deflate compression without >>> + compression header >> Why did you name it "deflate" instead of "zlib" again? > > zlib provides raw deflate encoding and gzip encoding both with and without > header afaik. > We use raw deflate encoding without header in QEMU. And the name of the > algorithm is deflate. > I found it more appropriate than zlib.
Okay, I can live with that. > >> >>> + >>> + 14: compress_level (uint8_t) >>> + >>> + 0 = default compress level (valid for all formats, >>> default) >>> + >>> + Additional valid compression levels for deflate >>> compression: >>> + >>> + All values between 1 and 9. 1 gives best speed, 9 gives >>> best >>> + compression. The default compression level is defined >>> by zlib >>> + and currently defaults to 6. >>> + >>> + 15: compress_window_size (uint8_t) >>> + >>> + Window or dictionary size used by the compression >>> format. >>> + Currently only used by the deflate compression >>> algorithm. >> What must this be set to for other algorithms? I guess we get to that >> in later patches. > > Its only used by the deflate algorithm. At this point we only have that > algorithm. > lzo has no such encoding. If we add e.g. lzma it has a dictionary size which > is > a power of two (typcial value would be 2^20). So for lzo, we should document that the field must be 0 (when we get to adding it). > > Can you also have a look at the remainder of the series? It's on my list for 2.11 reviews, although 2.10 freeze stuff is taking priority, so it may be a few days yet. -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3266 Virtualization: qemu.org | libvirt.org
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