Igor Pavlov (7z/LZMA SDK author) told me a few months ago that
> Decompression speed for lzma:
> lzma sdk 18.03 C code - about +120% speed increase from 4.42.
> lzma sdk 18.03 asm-x64 code - about +180% speed increase from 4.42.
Although he didn't mention any compression ratio changes, maybe
because they're not big enough,
this such a huge speed increase alone should be a good reason to
upgrade these LZMA libraries.

ср, 4 апр. 2018 г. в 11:19, Carl-Daniel Hailfinger
<[email protected]>:
>
> Hi Ivan,
>
> On 03.04.2018 20:03, Ivan Ivanov wrote:
> > I have noticed that both coreboot and seabios are using the very old
> > versions of LZMA SDK.
>
> True. I introduced the lzma code in coreboot (back when it was called
> LinuxBIOS) when we were working on OLPC XO-1 support.
>
>
> > If we will upgrade our LZMA libraries from the
> > outdated-by-12-years 4.42 to the current version 18.04 , speed and
> > compression ratio should improve and maybe a few bugs will be fixed.
>
> Do you have any numbers for this? An improved compression ratio and
> improved speed would be nice indeed, but how does the size of the
> decompression code change? If the decompression code grows more than the
> size reduction from better compression, it would be a net loss. A
> significantly reduced decompression speed would also be a problem.
> Decompression speed would have to be measured both for stream
> decompression (i.e. the decompressor gets the compressed data in
> single-byte or multibyte chunks) as well as full-size decompression
> (i.e. the decompressor can access all compressed data at once). We also
> have to make sure that stream decompression still works after the change.
>
>
> > Do you think it should be done, or you are OK with using such an
> > outdated version?
>
> A size benefit for the resulting image is a good reason to switch.
>
> Regards,
> Carl-Daniel
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