From patchwork Wed May 20 19:36:36 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nick Desaulniers X-Patchwork-Id: 11561119 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 B1CD6739 for ; Wed, 20 May 2020 19:36:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 92FAE20758 for ; Wed, 20 May 2020 19:36:44 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="NLqxSrFn" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726810AbgETTgo (ORCPT ); Wed, 20 May 2020 15:36:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48028 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726560AbgETTgo (ORCPT ); Wed, 20 May 2020 15:36:44 -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 C5656C061A0F for ; Wed, 20 May 2020 12:36:43 -0700 (PDT) Received: by mail-yb1-xb4a.google.com with SMTP id z7so2840168ybn.21 for ; Wed, 20 May 2020 12:36:43 -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=AVVfiQR/7pisBCGTKoQl1KucA/6VNUwh3DKASPprRvc=; b=NLqxSrFnKkZcAGnV8zbrPjaSqtdTtqC6WvnCQ6SzwmjdO1Y1A4F8KO5jePbf4Ld4vU 28TZNpeQFNkATsX+wqdm37YvRNjMEIJWOynydl7FMOR9zWc2pJMGJ/dm0ByXmA3wOy6f jEyGYA4c992ndf4FDE2XNOvJHqfNQkgp29X6JoGzCqYzfY6kPRseR8x89YXJLR67lkNi tb/oT6vlfiQs/gPcIri5IW4wS0mr2Ln1pssXe77Az1wxZw93TVFzUCSWqhO0oeLFPAfe dYcLUAA/fVV0ZOQy7v/R+8oS99/oCi9P0XhQli9FNC18szcQtd/4G7ZjiZx+ArvXOIfe ejJg== 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=AVVfiQR/7pisBCGTKoQl1KucA/6VNUwh3DKASPprRvc=; b=LGlMuAQWfSWk6wNgHJjadqm1LqR2Bs853wRL039hnrFRSMV5qhPnypJ5rfPKUJ5X3G pXesBDTcKhdVmn+io1m3XN0QGOCnsI3ZL8Pnau3gksJ0AjXRK0rgdKbmG9pwrnIoEYOG DNwqFOYGPJ5b3RypUbj5aHRpvonRN1lLI6vWHIsCf6z3REFIyC6m2d3/4lVKxDAjdI/m Ki9bQS6PUAjBpAKEffkRyUvSGBTLx5LRF73tUVF+LCTueUCDGu4s1VPC9V4AQdriJDRm dfCC7rKVqznWGxj11CGjCTRGDMnS5tt3wXW46p0/NNOu/jbYVwebshebfHFZ4cNszkg2 Femw== X-Gm-Message-State: AOAM5313AYcqQW1RtQkJougAzoThkbRgC7mBe/Kn7byS8KCA3Lkh5eMd mGu/0yumX+f3SHHdjKvPGk4a0nfqV6lT9fVcrLY= X-Google-Smtp-Source: ABdhPJwbmZUSDN6st0s//rLv1KZNYKNcyqaF9cXBCgx9X5BHJdWUMRAcv2Kb8IflvnhjGtC0I4kw9o2KKivp+wgPlNc= X-Received: by 2002:a25:73d2:: with SMTP id o201mr8570814ybc.490.1590003402844; Wed, 20 May 2020 12:36:42 -0700 (PDT) Date: Wed, 20 May 2020 12:36:36 -0700 In-Reply-To: <10f4fb0b-1012-b0e6-af05-0aa5a906de21@redhat.com> Message-Id: <20200520193637.6015-1-ndesaulniers@google.com> Mime-Version: 1.0 References: <10f4fb0b-1012-b0e6-af05-0aa5a906de21@redhat.com> X-Mailer: git-send-email 2.26.2.761.g0e0b3e54be-goog Subject: [PATCH v2] 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 Suggested-by: David Blaikie Suggested-by: Fangrui Song Suggested-by: Nick Clifton Suggested-by: Sedat Dilek Tested-by: Sedat Dilek Signed-off-by: Nick Desaulniers --- 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 | 15 +++++++++++++++ 2 files changed, 21 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..5a423cbfaea4 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -225,6 +225,21 @@ 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,--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 + wish to set the $KDEB_COMPRESS env var to "none" to avoid recompressing + the debug info again with a different compression scheme, which can + result in larger binaries. + config DEBUG_INFO_SPLIT bool "Produce split debuginfo in .dwo files" depends on DEBUG_INFO