On 3/4/22 10:09 AM, Michael Olbrich wrote:
On Thu, Mar 03, 2022 at 11:25:05PM +0100, Christian Melki wrote:
* xz needs crc32 instead of crc64 for the kernel cpio.
Good point. I didn't know about that.
* Set zstd compression level to the same as for the kernel (19).
Makes sense.
* Use multithreading for zstd (deterministic, afaiu).
It is. I looked into this because I was curious. And it makes sense. zstd
was developed at a time when reproducibility was already important.
Actively decided against -T0 for xz, as compression
is not deterministic when number of threads varies.
We definitively want to be reproducible here.
Signed-off-by: Christian Melki <[email protected]>
---
rules/image-root-cpio.make | 3 +++
1 file changed, 3 insertions(+)
diff --git a/rules/image-root-cpio.make b/rules/image-root-cpio.make
index fdb0ccfff..eb09dd53e 100644
--- a/rules/image-root-cpio.make
+++ b/rules/image-root-cpio.make
@@ -26,6 +26,9 @@ IMAGE_ROOT_CPIO_CONFIG := cpio.config
IMAGE_ROOT_CPIO_ENV := \
FORMAT="newc" \
+ ZSTD_CLEVEL="19" \
+ ZSTD_NBTHREADS="0" \
+ XZ_OPT="--check=crc32" \
COMPRESS=$(call remove_quotes,
$(PTXCONF_IMAGE_ROOT_CPIO_COMPRESSION_UTIL))
Add the options to the PTXCONF_IMAGE_ROOT_CPIO_COMPRESSION_UTIL defaults
and keep the quotes here:
COMPRESS=$(PTXCONF_IMAGE_ROOT_CPIO_COMPRESSION_UTIL)
genimage explicitly does not quote to make to possible to specify the
compressor with options. At least I thinks that should work.
And maybe we could add a IMAGE_ROOT_CPIO_COMPRESSION_MODE_CUSTOM and then
add 'prompt "suffix" if IMAGE_ROOT_CPIO_COMPRESSION_MODE_CUSTOM' to the
suffix and similar for the util.
This way the user could tweak things if absolutely necessary.
What do you think?
I don't mind, will fix. But custom compressors will be outside of the
ptxdist dependency scope for building host binaries?
I can make a note about it in the help?
Michael
ifdef PTXCONF_IMAGE_ROOT_CPIO
--
2.30.2
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