@cborntra
v5.13 ubuntu kernel's s390 configuration with zstd -22 --ultra compression is 8.5 MB, whereas gzip -9 is 11M.
Thus for gzip to win at bootspeed the decompression speed has to compensate for 2.5M of i/o and be faster than zstd.
Unaccelerated decompression comparison still gives me faster decompression with less i/o with zstd compressed kernel image.
At Canonical we still do not have z15 mainframe available for us to benchmark this.
@cborntra
v5.13 ubuntu kernel's s390 configuration with zstd -22 --ultra compression is 8.5 MB, whereas gzip -9 is 11M.
Thus for gzip to win at bootspeed the decompression speed has to compensate for 2.5M of i/o and be faster than zstd.
Unaccelerated decompression comparison still gives me faster decompression with less i/o with zstd compressed kernel image.
At Canonical we still do not have z15 mainframe available for us to benchmark this.