From patchwork Tue May 26 17:18:29 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nick Desaulniers X-Patchwork-Id: 11570875 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id DB72914B7 for ; Tue, 26 May 2020 17:18:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BE3FA2073B for ; Tue, 26 May 2020 17:18:39 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="aV+EtZWf" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728594AbgEZRSj (ORCPT ); Tue, 26 May 2020 13:18:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44806 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728523AbgEZRSi (ORCPT ); Tue, 26 May 2020 13:18:38 -0400 Received: from mail-yb1-xb49.google.com (mail-yb1-xb49.google.com [IPv6:2607:f8b0:4864:20::b49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id ADE75C03E96D for ; Tue, 26 May 2020 10:18:38 -0700 (PDT) Received: by mail-yb1-xb49.google.com with SMTP id v1so21231297ybo.23 for ; Tue, 26 May 2020 10:18:38 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=qz8XL5HjRypO1RoMKqirUSXQ6SNzxq1AQO7Af1uk7eg=; b=aV+EtZWfxq8hZz390kw22ff2bERfaAxS+NwmsZdiIUYAvoCIzy6goI4eJRxT3jrPh8 xZYkVZxurB1Lv/uWfUfFZ3pJ5UsvfeEIXy854tkDM9LazUXsuIeOmUybAr4CYx3HQmVF qyGFlExpbOoOyFc7nVlxMSoptdyr/Q9z8Xo/uO/3QgOoZd9/YiPasUywI8nfmj9Vlg8u IVLFQthtuCm0vWlOg2NN9zs23tyOQBP6RENrKAVbXKWf/MOCFN11o2vkNBkxIN20dZzL RqrWSqv9lpx2dbFJ6M0CSj/EZEFGfKqE1UBO6lue5FJgw9NbeGY1eKIIgrXnUwRlX98o rIBw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=qz8XL5HjRypO1RoMKqirUSXQ6SNzxq1AQO7Af1uk7eg=; b=LVWeT6AnKwYVb3nz2d4uGb1e3OIwVoVLGhvFkDRjdCUwi3s1fBmodKEOe0PG5juoaI WYa+eKvFep36E5wOvUwRK/zP0ZSQwhGKI0vgWKDF5zRgvq9/AZhI0RjZDqknu5snOkcr JKOoMxsrSPCEquYUmSRyl5bQAlfwURO+TZbzew1ThXuKoi1YZT3LjWDfJ8yomuKDxqZD wpsfLgQd7anM/38VTfN2HmJqoHojVjz9/t+3JlEAh4LEI/ddexRSBZYWEIvQCTA6rPxJ m4nOmmte92AHPTrJ+NkxDQ/wGAVeVcw5vKeffLrSgZ0TeCNB1lSSNTY7f8jGWLxnljOr Q1nw== X-Gm-Message-State: AOAM531NeGTDNBBqAJWA//5Q4p4CwMyGRXcU3aqdulyTnr+45VLo/r6E P21j1sV9D4m/9Pqh+jqhVebDY54R91kZwtAKPcs= X-Google-Smtp-Source: ABdhPJxDPm+wkkMpsgRhYQTwpsCoaf6b9kFkH+TSAz8TH+6AQcwtg18bXA+ESWI7ZJpAj2iTVtikPUMoMUzhnggZv7s= X-Received: by 2002:a25:253:: with SMTP id 80mr3241130ybc.405.1590513517344; Tue, 26 May 2020 10:18:37 -0700 (PDT) Date: Tue, 26 May 2020 10:18:29 -0700 In-Reply-To: Message-Id: <20200526171830.151966-1-ndesaulniers@google.com> Mime-Version: 1.0 References: X-Mailer: git-send-email 2.27.0.rc0.183.gde8f92d652-goog Subject: [PATCH v5] Makefile: support compressed debug info From: Nick Desaulniers To: Masahiro Yamada Cc: Sedat Dilek , Fangrui Song , Nick Clifton , Nick Desaulniers , David Blaikie , Michal Marek , Andrew Morton , Changbin Du , Randy Dunlap , Stephen Rothwell , Mauro Carvalho Chehab , Anshuman Khandual , Krzysztof Kozlowski , linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com Sender: linux-kbuild-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kbuild@vger.kernel.org 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 $ 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 Thanks to: Nick Clifton helped us to provide the minimal binutils version. Sedat Dilet found an increase in size of debug .deb package. Cc: Nick Clifton Cc: Sedat Dilek Suggested-by: David Blaikie Reviewed-by: Fangrui Song Tested-by: Sedat Dilek Signed-off-by: Nick Desaulniers --- Changes V4 -> V5: * Drop unrelated hunk from a dirty tree. Changes V3 -> V4: * Add thanks line to commit message as per Masahiro. * Swap Sugguested-by to Cc for two lines in commit message, as per Masahiro. 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