From: Sedat Dilek <sedat.dilek@gmail.com>
To: Nick Desaulniers <ndesaulniers@google.com>
Cc: Masahiro Yamada <masahiroy@kernel.org>,
Fangrui Song <maskray@google.com>,
Nick Clifton <nickc@redhat.com>,
David Blaikie <blaikie@google.com>,
Michal Marek <michal.lkml@markovi.net>,
Andrew Morton <akpm@linux-foundation.org>,
Changbin Du <changbin.du@intel.com>,
Randy Dunlap <rdunlap@infradead.org>,
Stephen Rothwell <sfr@canb.auug.org.au>,
Anshuman Khandual <anshuman.khandual@arm.com>,
Mauro Carvalho Chehab <mchehab+huawei@kernel.org>,
Krzysztof Kozlowski <krzk@kernel.org>,
linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org,
Clang-Built-Linux ML <clang-built-linux@googlegroups.com>
Subject: Re: [PATCH v3] Makefile: support compressed debug info
Date: Fri, 22 May 2020 13:56:59 +0200 [thread overview]
Message-ID: <CA+icZUWGB8bp1UZHQpB_W8YL7SeN23h5V9NTq-p3jeUqO4MK+w@mail.gmail.com> (raw)
In-Reply-To: <20200521220041.87368-1-ndesaulniers@google.com>
On Fri, May 22, 2020 at 12:00 AM Nick Desaulniers
<ndesaulniers@google.com> wrote:
>
> As debug information gets larger and larger, it helps significantly save
> the size of vmlinux images to compress the information in the debug
> information sections. Note: this debug info is typically split off from
> the final compressed kernel image, which is why vmlinux is what's used
> in conjunction with GDB. Minimizing the debug info size should have no
> impact on boot times, or final compressed kernel image size.
>
> All of the debug sections will have a `C` flag set.
> $ readelf -S <object file>
>
> $ bloaty vmlinux.gcc75.compressed.dwarf4 -- \
> vmlinux.gcc75.uncompressed.dwarf4
>
> FILE SIZE VM SIZE
> -------------- --------------
> +0.0% +18 [ = ] 0 [Unmapped]
> -73.3% -114Ki [ = ] 0 .debug_aranges
> -76.2% -2.01Mi [ = ] 0 .debug_frame
> -73.6% -2.89Mi [ = ] 0 .debug_str
> -80.7% -4.66Mi [ = ] 0 .debug_abbrev
> -82.9% -4.88Mi [ = ] 0 .debug_ranges
> -70.5% -9.04Mi [ = ] 0 .debug_line
> -79.3% -10.9Mi [ = ] 0 .debug_loc
> -39.5% -88.6Mi [ = ] 0 .debug_info
> -18.2% -123Mi [ = ] 0 TOTAL
>
> $ bloaty vmlinux.clang11.compressed.dwarf4 -- \
> vmlinux.clang11.uncompressed.dwarf4
>
> FILE SIZE VM SIZE
> -------------- --------------
> +0.0% +23 [ = ] 0 [Unmapped]
> -65.6% -871 [ = ] 0 .debug_aranges
> -77.4% -1.84Mi [ = ] 0 .debug_frame
> -82.9% -2.33Mi [ = ] 0 .debug_abbrev
> -73.1% -2.43Mi [ = ] 0 .debug_str
> -84.8% -3.07Mi [ = ] 0 .debug_ranges
> -65.9% -8.62Mi [ = ] 0 .debug_line
> -86.2% -40.0Mi [ = ] 0 .debug_loc
> -42.0% -64.1Mi [ = ] 0 .debug_info
> -22.1% -122Mi [ = ] 0 TOTAL
>
> For x86_64 defconfig + LLVM=1 (before):
> Elapsed (wall clock) time (h:mm:ss or m:ss): 3:22.03
> Maximum resident set size (kbytes): 43856
>
> For x86_64 defconfig + LLVM=1 (after):
> Elapsed (wall clock) time (h:mm:ss or m:ss): 3:32.52
> Maximum resident set size (kbytes): 1566776
>
> Suggested-by: David Blaikie <blaikie@google.com>
> Suggested-by: Nick Clifton <nickc@redhat.com>
> Suggested-by: Sedat Dilek <sedat.dilek@gmail.com>
> Reviewed-by: Fangrui Song <maskray@google.com>
> Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Re-tested V3 on top of Linux v5.7-rc6+ with Clang/LLD v10.0.1-rc1.
- Sedat -
> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
> ---
> Changes V2 -> V3:
> * Fix blaikie@'s email addr.
> * Fix Fangrui's Reviewed-by tag as per Masahiro.
> * Fix help text as per Masahiro.
> * Fix -Wa$(comma)foo as per Masahiro.
>
> Changes V1 -> V2:
> * rebase on linux-next.
> * Add assembler flags as per Fangrui.
> * Add note about KDEB_COMPRESS+scripts/package/builddeb
> as per Sedat and Masahiro.
> * Add note about bintutils version requirements as per Nick C.
> * Add note about measured increased build time and max RSS.
> Makefile | 6 ++++++
> lib/Kconfig.debug | 17 +++++++++++++++++
> 2 files changed, 23 insertions(+)
>
> diff --git a/Makefile b/Makefile
> index 71687bfe1cd9..be8835296754 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -822,6 +822,12 @@ DEBUG_CFLAGS += $(call cc-option, -femit-struct-debug-baseonly) \
> $(call cc-option,-fno-var-tracking)
> endif
>
> +ifdef CONFIG_DEBUG_INFO_COMPRESSED
> +DEBUG_CFLAGS += -gz=zlib
> +KBUILD_AFLAGS += -Wa,--compress-debug-sections=zlib
> +KBUILD_LDFLAGS += --compress-debug-sections=zlib
> +endif
> +
> KBUILD_CFLAGS += $(DEBUG_CFLAGS)
> export DEBUG_CFLAGS
>
> diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
> index b8f023e054b9..7fc82dcf814b 100644
> --- a/lib/Kconfig.debug
> +++ b/lib/Kconfig.debug
> @@ -225,6 +225,23 @@ 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"
> + depends on DEBUG_INFO
> + depends on $(cc-option,-gz=zlib)
> + depends on $(as-option,-Wa$(comma)--compress-debug-sections=zlib)
> + depends on $(ld-option,--compress-debug-sections=zlib)
> + help
> + Compress the debug information using zlib. Requires GCC 5.0+ or Clang
> + 5.0+, binutils 2.26+, and zlib.
> +
> + Users of dpkg-deb via scripts/package/builddeb may find an increase in
> + size of their debug .deb packages with this config set, due to the
> + debug info being compressed with zlib, then the object files being
> + recompressed with a different compression scheme. But this is still
> + preferable to setting $KDEB_COMPRESS to "none" which would be even
> + larger.
> +
> config DEBUG_INFO_SPLIT
> bool "Produce split debuginfo in .dwo files"
> depends on DEBUG_INFO
> --
> 2.27.0.rc0.183.gde8f92d652-goog
>
next prev parent reply other threads:[~2020-05-22 11:57 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-04 3:13 [PATCH] Makefile: support compressed debug info Nick Desaulniers
2020-05-04 16:25 ` Sedat Dilek
2020-05-05 0:47 ` Fangrui Song
2020-05-12 5:53 ` Masahiro Yamada
2020-05-12 19:23 ` Nick Desaulniers
2020-05-12 20:01 ` Fangrui Song
2020-05-12 20:06 ` Sedat Dilek
2020-05-13 19:00 ` Nick Desaulniers
2020-05-14 11:34 ` Nick Clifton
2020-05-20 19:36 ` [PATCH v2] " Nick Desaulniers
2020-05-20 23:21 ` Nick Desaulniers
2020-05-20 23:22 ` Andrew Morton
2020-05-21 2:47 ` Masahiro Yamada
2020-05-21 21:57 ` Nick Desaulniers
2020-05-21 22:00 ` [PATCH v3] " Nick Desaulniers
2020-05-22 11:56 ` Sedat Dilek [this message]
2020-05-26 10:26 ` Masahiro Yamada
2020-05-26 15:53 ` Nick Desaulniers
2020-05-26 16:15 ` Masahiro Yamada
2020-05-26 17:03 ` [PATCH v4] " Nick Desaulniers
2020-05-26 17:06 ` Nick Desaulniers
2020-05-26 17:18 ` [PATCH v5] " Nick Desaulniers
2020-05-24 3:56 ` [PATCH v2] " Masahiro Yamada
2020-05-24 7:48 ` Sedat Dilek
2020-05-26 15:58 ` Nick Desaulniers
2020-05-12 20:02 ` [PATCH] " Sedat Dilek
2020-05-13 2:51 ` Masahiro Yamada
2020-05-13 16:33 ` Sedat Dilek
2020-05-12 5:46 ` Masahiro Yamada
2020-05-12 8:59 ` Sedat Dilek
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=CA+icZUWGB8bp1UZHQpB_W8YL7SeN23h5V9NTq-p3jeUqO4MK+w@mail.gmail.com \
--to=sedat.dilek@gmail.com \
--cc=akpm@linux-foundation.org \
--cc=anshuman.khandual@arm.com \
--cc=blaikie@google.com \
--cc=changbin.du@intel.com \
--cc=clang-built-linux@googlegroups.com \
--cc=krzk@kernel.org \
--cc=linux-kbuild@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=masahiroy@kernel.org \
--cc=maskray@google.com \
--cc=mchehab+huawei@kernel.org \
--cc=michal.lkml@markovi.net \
--cc=ndesaulniers@google.com \
--cc=nickc@redhat.com \
--cc=rdunlap@infradead.org \
--cc=sfr@canb.auug.org.au \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).