commit: 6834e464803b5ac98f8ab1bbca5379970b5bc6d9
Author: Sam James <sam <AT> gentoo <DOT> org>
AuthorDate: Fri Oct 21 01:32:17 2022 +0000
Commit: Sam James <sam <AT> gentoo <DOT> org>
CommitDate: Fri Oct 21 01:32:17 2022 +0000
URL: https://gitweb.gentoo.org/proj/portage.git/commit/?id=6834e464
ecompress: don't set -9 for xz
>From xz(1):
"""
The differences between the presets are more significant than with gzip(1) and
bzip2(1). The selected compression settings determine the memory requirements
of the decompressor, thus us‐
ing a too high preset level might make it painful to decompress the file on an
old system with little RAM. Specifically, it's not a good idea to blindly use
-9 for everything like it of‐
ten is with gzip(1) and bzip2(1).
[...]
-7 ... -9
These are like -6 but with higher compressor and decompressor memory
requirements. These are useful only when compressing files bigger than 8 MiB,
16 MiB, and 32 MiB, respectively.
[...]
• DictSize is the LZMA2 dictionary size. It is waste of memory to use a
dictionary bigger than the size of the uncompressed file. This is why it is
good to avoid using the presets -7
... -9 when there's no real need for them. At -6 and lower, the amount of
memory wasted is usually low enough to not matter.
"""
Most things that ecompress touches are tiny (<32MB certainly). I made the
mistake the man page warngs about -- don't assume it's a good idea just
because of gzip & bzip2, and that's exactly what I did!
Signed-off-by: Sam James <sam <AT> gentoo.org>
bin/ecompress | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/bin/ecompress b/bin/ecompress
index 78a53ccac..609814cca 100755
--- a/bin/ecompress
+++ b/bin/ecompress
@@ -128,7 +128,7 @@ if [[ ${PORTAGE_COMPRESS_FLAGS+set} != "set" ]] ; then
# See: https://bugs.gentoo.org/672916
# Setting '--rm' will remove the source files after a
successful compression.
lz4) PORTAGE_COMPRESS_FLAGS="-m --rm";;
- xz) PORTAGE_COMPRESS_FLAGS="-9 -T$(___makeopts_jobs)
--memlimit-compress=50% -q";;
+ xz) PORTAGE_COMPRESS_FLAGS="-q -T$(___makeopts_jobs)
--memlimit-compress=50%";;
zstd) PORTAGE_COMPRESS_FLAGS="-q --rm -T$(___makeopts_jobs)";;
esac
fi
