On 5/29/19 11:19 PM, Ben Cotton wrote:
* The macro for setting the compression is: %define _binary_payload
w19.zstdio
* The recommended compression level is 19. The builds will take
longer, but the additional compression time is negligible in the total
build time and it pays off in better compression ratio than xz lvl2
has.
This is what we always thought with rpmbuild, "no point optimizing
because it'll just get drowned in the noise". However this has gotten to
be a hot topic in the last year or so, with people from different
backgrounds wanting to parallelize various aspects of rpmbuild to speed
it up.
To that background, going from 9m55s compression time to 24m2s is a
HORRIBLE regression that will eat away all the gains we just managed to
scrape by parallelizing new things.
Note that rpm doesn't support parallel zstd compression, and while it
does for xz, that's not even utilized in Fedora.
To me the sweet spot between compression efficiency and speed seems
closer to 10 than 19 - yes at a minor loss in space but huge speedup in
both compress and decompress times.
- pANU -