Docker is indeed looking for a "unpigz" executable to use: https://github.com/moby/moby/blob/c9d2b7df777b38f7239a882c27c763f3c9cda9c3/pkg/archive/archive.go#L21

Docker is indeed looking for a "unpigz" executable to use: https://github.com/moby/moby/blob/c9d2b7df777b38f7239a882c27c763f3c9cda9c3/pkg/archive/archive.go#L210 https://github.com/moby/moby/blob/c9d2b7df777b38f7239a882c27... So interesting if they implemented and tested that and get only a marginal CRC speedup. edit: someone here seems to observe a ~ doubling with unpigz vs zcat: https://unix.stackexchange.com/a/363739 https://unix.stackexchange.com/a/363739