Re: [PATCH] dist: add dist-zstd option

[Giuseppe Scrivano]

Hi Jim,

Jim Meyering <address@hidden> writes:

> On Fri, Oct 4, 2019 at 8:03 AM Giuseppe Scrivano <address@hidden> wrote:
>> add support for using the zstd compression algorithm.
>
> Hi Giuseppe,
> Thank you for that patch.
> I've adjusted it and propose the attached, which makes these changes:
> - add tests
> - that exposed the need for a correction, s/-d/-dc/ in distdir.am
> - extend documentation
> - use the 3-byte suffix, .zst, not .zstd
> - use -19 as the default compression level
>
> We must use -19 as the default, not the aggressive --ultra -22 -- the
> package maintainer can always override with ZSTD_OPT if they know all
> clients will always have sufficient memory. In the early days, some
> reported failure to decompress a "xz -9e"-compressed coreutils tarball
> on tiny-memory routers. Like zstd's --ultra settings, xz's -9 requires
> more RAM when DEcompressing -- so automake defaults to xz's "-e" (use
> extra CPU only) and used -e8 for coreutils
> (https://git.sv.gnu.org/cgit/coreutils.git/commit/?id=v8.15-61-gc1d07237a):
> i.e., still require 32MiB more RAM, but not the 64MiB that "-9" would
> require.
>
> Cc'd the zstd author, Yann Collet, in case he'd like to add something.
>
> Giuseppe, please re-review this diff and its updated commit log.

thanks for the fixes.  The updated patch looks good to me.

Giuseppe