Make DEBUG_INFO_COMPRESSED a choice; DEBUG_INFO_UNCOMPRESSED is the default, DEBUG_INFO_COMPRESSED uses zlib, DEBUG_INFO_COMPRESSED_ZSTD uses zstd. 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_UNCOMPRESSED=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=y (zlib): 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 (zstd): 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. This renames the existing KConfig options: * DEBUG_INFO_UNCOMPRESSED -> DEBUG_INFO_COMPRESSED_NONE * DEBUG_INFO_COMPRESSED -> DEBUG_INFO_COMPRESSED_ZLIB So users upgrading may need to reset the new Kconfigs. 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@xxxxxxx> Reviewed-by: Nathan Chancellor <nathan@xxxxxxxxxx> Signed-off-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx> --- Changes v1 -> v2: * Remove `depends on DEBUG_KERNEL` as per Nathan. * Rename Kconfigs as per Sedat and Masahiro. * Add note about renamed Kconfigs to commit message. * Add more help text to DEBUG_INFO_COMPRESSED_ZSTD. lib/Kconfig.debug | 29 +++++++++++++++++++++++++++-- scripts/Makefile.debug | 4 ++++ 2 files changed, 31 insertions(+), 2 deletions(-) diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 29280072dc0e..7c28a8fba02e 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -312,8 +312,21 @@ config DEBUG_INFO_REDUCED DEBUG_INFO build and compile times are reduced too. Only works with newer gcc versions. -config DEBUG_INFO_COMPRESSED - bool "Compressed debugging information" +choice + prompt "Compressed Debug information" + help + Compress the resulting debug info. Results in smaller debug info sections, + but requires that consumers are able to decompress the results. + + If unsure, choose DEBUG_INFO_COMPRESSED_NONE. + +config DEBUG_INFO_COMPRESSED_NONE + bool "Don't compress debug information" + help + Don't compress debug info sections. + +config DEBUG_INFO_COMPRESSED_ZLIB + bool "Compress debugging information with zlib" depends on $(cc-option,-gz=zlib) depends on $(ld-option,--compress-debug-sections=zlib) help @@ -327,6 +340,18 @@ config DEBUG_INFO_COMPRESSED preferable to setting $KDEB_COMPRESS to "none" which would be even larger. +config DEBUG_INFO_COMPRESSED_ZSTD + bool "Compress debugging information with zstd" + depends on $(cc-option,-gz=zstd) + depends on $(ld-option,--compress-debug-sections=zstd) + help + Compress the debug information using zstd. This may provide better + compression than zlib, for about the same time costs, but requires newer + toolchain support. Requires GCC 13.0+ or Clang 16.0+, binutils 2.40+, and + zstd. + +endchoice # "Compressed Debug information" + config DEBUG_INFO_SPLIT bool "Produce split debuginfo in .dwo files" depends on $(cc-option,-gsplit-dwarf) diff --git a/scripts/Makefile.debug b/scripts/Makefile.debug index 332c486f705f..8ac3379d2255 100644 --- a/scripts/Makefile.debug +++ b/scripts/Makefile.debug @@ -31,6 +31,10 @@ ifdef CONFIG_DEBUG_INFO_COMPRESSED DEBUG_CFLAGS += -gz=zlib KBUILD_AFLAGS += -gz=zlib KBUILD_LDFLAGS += --compress-debug-sections=zlib +else ifdef CONFIG_DEBUG_INFO_COMPRESSED_ZSTD +DEBUG_CFLAGS += -gz=zstd +KBUILD_AFLAGS += -gz=zstd +KBUILD_LDFLAGS += --compress-debug-sections=zstd endif KBUILD_CFLAGS += $(DEBUG_CFLAGS) base-commit: f0c4d9fc9cc9462659728d168387191387e903cc -- 2.38.1.431.g37b22c650d-goog
