From patchwork Thu May 21 22:00:40 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nick Desaulniers X-Patchwork-Id: 11564111 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 62258138A for ; Thu, 21 May 2020 22:00:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4977920748 for ; Thu, 21 May 2020 22:00:52 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="YfIck0fB" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730405AbgEUWAt (ORCPT ); Thu, 21 May 2020 18:00:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41184 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729370AbgEUWAt (ORCPT ); Thu, 21 May 2020 18:00:49 -0400 Received: from mail-yb1-xb4a.google.com (mail-yb1-xb4a.google.com [IPv6:2607:f8b0:4864:20::b4a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C527AC061A0E for ; Thu, 21 May 2020 15:00:48 -0700 (PDT) Received: by mail-yb1-xb4a.google.com with SMTP id 5so6955886ybe.17 for ; Thu, 21 May 2020 15:00:48 -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=aKUpBFPk5Djn/rrzBrR97m/tGbj33/YMXzpAfYT/Utg=; b=YfIck0fBt7ZzzuTMrr5pga7iKwpjiyj+4n/07wlqGVK9mgcIabVUzrNa4nO4j7OtP+ reVeuIbakaXGmwIynLZ8dYPg7eMq9ZhCF/fwU1gHuwru6vq+uvWVsJBgo6yQMRiQk2VO gqlaLQwxWr15H6Wi/Tv+vEnL7/nTmz3K3rJd0V0y7aMEd+JNBAK8uxalc8ZSqzD2IPmn 0nrb3LhcgjJ0LpMYcWNfSsswtnXMzh99mH1u8/c13xBp/9b7aH1bGNncdV/T2PxPgsPE bER9J08JrOXSQKnziH2/fuMX4ZscwDwa2XrjoN8noC1kFcSMRdJdngd1QGCUTqQOpJnE 758w== 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=aKUpBFPk5Djn/rrzBrR97m/tGbj33/YMXzpAfYT/Utg=; b=BexQ6CoARXOXWaC2YKNmPhBaCHY3vyoX61BWdWU2vlWDh21u5haXQtU9RLd2gv/xke tQ4mlqPSAqQppfF/zL/RK/nmZq7xKaY5Q104XzCohlCOSws0rd9+lz1LpBMW1aRvDyRW mKx30xbLqZ+SVAcuv08oT44XrpxYIYFJrCvYdIqKS0C67ofwt+wsosWYrLGWUDNWSM6f FpkaymQK6eveqsXs4biWoKzNl+sCIbfQ5NONU64bK9pLKH2jklTUiXefyDbN7OF03Pwp kaJkouVvPf5opYsT15OlHoV2rkwg1u+iI8DT5jpGk0DmkNkpmK/Ih5115mbg+7Vuewny /1Kw== X-Gm-Message-State: AOAM530qnAg0ewi8PG1jNpetrBDoLrWIK7JUoqGGNrzll/KR32vWLNXI e6Tkg1ThnTuPeShYwluye9Oi9CIwDkHMOuDuT7U= X-Google-Smtp-Source: ABdhPJxWbiv3OFdS/gVrZqGmjfHKBwB+yz9rWYVA+P3KukhI6r49sD9dEtv7tc/9vEuxkF4xjN2PcOAPuI0dz9JEc2s= X-Received: by 2002:a25:4207:: with SMTP id p7mr17146898yba.424.1590098447910; Thu, 21 May 2020 15:00:47 -0700 (PDT) Date: Thu, 21 May 2020 15:00:40 -0700 In-Reply-To: Message-Id: <20200521220041.87368-1-ndesaulniers@google.com> Mime-Version: 1.0 References: X-Mailer: git-send-email 2.27.0.rc0.183.gde8f92d652-goog Subject: [PATCH v3] 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 , Anshuman Khandual , Mauro Carvalho Chehab , 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 Suggested-by: David Blaikie Suggested-by: Nick Clifton Suggested-by: Sedat Dilek Reviewed-by: Fangrui Song Tested-by: Sedat Dilek Signed-off-by: Nick Desaulniers --- 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