ipk: Switch to using zstd compression

Converts IPK package generation to use zstd instead of xz. zstd has a
much larger compression/speed tradeoff range allowing users to choose
what suits them best, and fast decompression speeds. It also continues
to support parallel compression as xz did.

A new variable called ZSTD_DEFAULTS is provided to set the defaults for
places that want to use zstd for compression; the zst image conversion
command is also modified to use this.

Finally, in order for this to function properly, opkg must include zstd
support, so it is enabled all the time with no PACKAGECONFIG to turn it
off.

(From OE-Core rev: 1bc3e9bbaa670b6128c74c76b4b5264e60ce3463)

Signed-off-by: Joshua Watt <JPEWhacker@gmail.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 4 insertions, 0 deletions

diff --git a/meta/conf/bitbake.conf b/meta/conf/bitbake.conf
index 83b12cbc15..b3f1f18a0d 100644
--- a/meta/conf/bitbake.conf
+++ b/meta/conf/bitbake.conf
@@ -878,6 +878,10 @@ XZ_DEFAULTS[vardepsexclude] += "XZ_MEMLIMIT XZ_THREADS"
 ZSTD_THREADS ?= "${@oe.utils.cpu_count(at_least=2)}"
 ZSTD_THREADS[vardepvalue] = "1"
 
+ZSTD_COMPRESSION_LEVEL ?= "-3"
+ZSTD_DEFAULTS ?= "--threads=${ZSTD_THREADS} ${ZSTD_COMPRESSION_LEVEL}"
+ZSTD_DEFAULTS[vardepsexclude] = "ZSTD_THREADS"
+
 # Limit the number of threads that OpenMP libraries will use. Otherwise they
 # may fallback to using all CPUs
 export OMP_NUM_THREADS = "${BB_NUMBER_THREADS}"