On Thu, Oct 20, 2022 at 10:56:49AM -0700, Nick Desaulniers wrote: > 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. > > 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> > Signed-off-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx> Reviewed-by: Nathan Chancellor <nathan@xxxxxxxxxx> One small comment below. > --- > lib/Kconfig.debug | 26 +++++++++++++++++++++++++- > scripts/Makefile.debug | 4 ++++ > 2 files changed, 29 insertions(+), 1 deletion(-) > > diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug > index 3fc7abffc7aa..4085ac77dc12 100644 > --- a/lib/Kconfig.debug > +++ b/lib/Kconfig.debug > @@ -312,8 +312,22 @@ config DEBUG_INFO_REDUCED > DEBUG_INFO build and compile times are reduced too. > Only works with newer gcc versions. > > +choice > + prompt "Compressed Debug information" > + depends on DEBUG_KERNEL I think you can drop this depends. The entire block is in an 'if DEBUG_INFO', which can only be true if CONFIG_DEBUG_KERNEL is set because of the dependencies of the "Debug information" prompt above this file, which is how CONFIG_DEBUG_INFO is selected. > + 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_UNCOMPRESSED. > + > +config DEBUG_INFO_UNCOMPRESSED > + bool "Don't compress debug information" > + help > + Don't compress debug info sections. > + > config DEBUG_INFO_COMPRESSED > - bool "Compressed debugging information" > + bool "Compress debugging information with zlib" > depends on $(cc-option,-gz=zlib) > depends on $(ld-option,--compress-debug-sections=zlib) > help > @@ -327,6 +341,16 @@ 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. 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) > -- > 2.38.0.135.g90850a2211-goog >
