Makefile.debug: support for -gz=zstd
Make DEBUG_INFO_COMPRESSED a choice; DEBUG_INFO_COMPRESSED_NONE is the
default, DEBUG_INFO_COMPRESSED_ZLIB uses zlib,
DEBUG_INFO_COMPRESSED_ZSTD uses zstd.
This renames the existing KConfig option DEBUG_INFO_COMPRESSED to
DEBUG_INFO_COMPRESSED_ZLIB so users upgrading may need to reset the new
Kconfigs.
Some quick N=1 measurements with du, /usr/bin/time -v, and bloaty:
clang-16, x86_64 defconfig plus
CONFIG_DEBUG_INFO=y CONFIG_DEBUG_INFO_COMPRESSED_NONE=y:
Elapsed (wall clock) time (h:mm:ss or m:ss): 0:55.43
488M vmlinux
27.6% 136Mi 0.0% 0 .debug_info
6.1% 30.2Mi 0.0% 0 .debug_str_offsets
3.5% 17.2Mi 0.0% 0 .debug_line
3.3% 16.3Mi 0.0% 0 .debug_loclists
0.9% 4.62Mi 0.0% 0 .debug_str
clang-16, x86_64 defconfig plus
CONFIG_DEBUG_INFO=y CONFIG_DEBUG_INFO_COMPRESSED_ZLIB=y:
Elapsed (wall clock) time (h:mm:ss or m:ss): 1:00.35
385M vmlinux
21.8% 85.4Mi 0.0% 0 .debug_info
2.1% 8.26Mi 0.0% 0 .debug_str_offsets
2.1% 8.24Mi 0.0% 0 .debug_loclists
1.9% 7.48Mi 0.0% 0 .debug_line
0.5% 1.94Mi 0.0% 0 .debug_str
clang-16, x86_64 defconfig plus
CONFIG_DEBUG_INFO=y CONFIG_DEBUG_INFO_COMPRESSED_ZSTD=y:
Elapsed (wall clock) time (h:mm:ss or m:ss): 0:59.69
373M vmlinux
21.4% 81.4Mi 0.0% 0 .debug_info
2.3% 8.85Mi 0.0% 0 .debug_loclists
1.5% 5.71Mi 0.0% 0 .debug_line
0.5% 1.95Mi 0.0% 0 .debug_str_offsets
0.4% 1.62Mi 0.0% 0 .debug_str
That's only a 3.11% overall binary size savings over zlib, but at no
performance regression.
Link: https://maskray.me/blog/2022-09-09-zstd-compressed-debug-sections
Link: https://maskray.me/blog/2022-01-23-compressed-debug-sections
Suggested-by: Sedat Dilek (DHL Supply Chain) <sedat.dilek@dhl.com>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
projects / linux-stable / commit