On Thu, Oct 20, 2022 at 8:43 PM Nathan Chancellor <nathan@xxxxxxxxxx> wrote: > > 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. > Yes, dropping this is good. > > + 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 Also, I prefer... DEBUG_INFO_COMPRESSED_NONE DEBUG_INFO_COMPRESSED_ZLIB DEBUG_INFO_COMPRESSED_ZSTD Following... $ ld.lld-16 -v Debian LLD 16.0.0 (compatible with GNU linkers) $ ld.lld-16 --help | grep compress-debug-sections --compress-debug-sections=[none,zlib,zstd] > > - 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. > > Anyone, checked $KDEB_COMPRESS - does this need changes? -Sedat- > > +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 > >
