From nobody Wed Nov 27 10:52:00 2024 Received: from mail-yb1-f202.google.com (mail-yb1-f202.google.com [209.85.219.202]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 140401E1A33 for ; Thu, 10 Oct 2024 19:24:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.219.202 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728588257; cv=none; b=c1PFzvtSoow8wrW3NxJCojf5hSkfFkA+EzR1cIIJbs0/RNK2knnzUiR2+oJ54Me9U3JyOioRtXvfsDSJ0wWBhY8pxGVKfD+QCx+FReWhPJNewhaWc3YcnpBQf0x8tI2NgCeyVmEX/zuVPb4PeiD6Pxfb6bKQFjS5G+6Cb7Kmnwk= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728588257; c=relaxed/simple; bh=sTdPsc9TlDcP9fj9qZnzf9a6N2MHYfNB5acRtfCguZg=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=u4QdCuwPc3XfjMHMvWw3Kdoyacrzomhf/DukMufa37KbvwbkzfWdu+WrfsYv/mwsFIphvKttqWm4uQUco/mvnpc7zmlaOfo37nvijXGfKBghlOviBc9MTKlsqaaPixBbIqzcfy1HGVq5QwMRsrll/QsZTN4E99gOe6Jp/pxPT9Q= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--xur.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=PSJSPEGc; arc=none smtp.client-ip=209.85.219.202 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--xur.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="PSJSPEGc" Received: by mail-yb1-f202.google.com with SMTP id 3f1490d57ef6-e290d41291bso1689290276.1 for ; Thu, 10 Oct 2024 12:24:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1728588254; x=1729193054; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=56GXdyw+jn4VfhhYEfGPQRjvArCzv+g18r0M8mTXpxs=; b=PSJSPEGc1ICrZR4kXlEtx0Rwvct4gMl1FL6geWt9CoeT31Aj1Htur6L9rMoVeQUSnC wEOAUkj+OzZnmuAf4Er9O7m3jfET+nuGYRjubK6+XOeQrQA+zLwWOnKBkfB1zdtEIUQS mgbaw9Y22REIA/D7bfTUQqn+aK9Tv/1SnHgJhzD9VjnmGHFKZdu34Z9BBTgphuBcq/4D JnsHDFbOrBdjbPqQUOL4F2Q/mwSaCXVWXMlN+cKk8SKoAwd5kfM93RRC2jbFfEC0EUFN BltEnFDFdo8lesO9AY4SZAtg374VFe6aKn5iV0MgCINFELLDM548NlZtxIZbqTQxV53/ eX+w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1728588254; x=1729193054; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=56GXdyw+jn4VfhhYEfGPQRjvArCzv+g18r0M8mTXpxs=; b=PNf6ljmfiYyA7GiMNI0F+s/aGsHl5gm616wmSoSU5KfyxCnK2KCzR6m5LXmS1b0AVO 93Bn/plj5Sx3BemaVoKepg93UrSWJ1RFLfeaLucd3sJVxAtymdMtFCaHOhqZ7HTUh/iV XoVlmCdXEsOudVE65hpfZM0d6Z5uZ1Vx7FrgbkjBfld11IcIbOFQS0uijVpWv+/u84NQ srY5oc1t3HakqvPWVch2nsJe6R9LhQzjlOzvyNdKik8ZPx8a+mipT6/fmD9dD1lNf13K 7IwjzQlgVvJW7b3ZDwlT4G6T7GDYa8JCZjM3xjKVro4douCodyy3fdjyUvDaXSEgc8Cn cYBA== X-Forwarded-Encrypted: i=1; AJvYcCXC4zoDxtZaJKiy7iD7kp7NKnxreohVzem3D74lMe6yN29A3aIEbXNT/eH5uZlqyKeC+kOv1CNOfExomrc=@vger.kernel.org X-Gm-Message-State: AOJu0YwI1md9ssuEG82y4LUV8egnIBEXwm2JFo1S12tFn9iSpDvMVOtV oAtSlNMdAxzNYGSnL6CQXG1Ob+nZ5Y7RdZW3T0NQsKdRFzfoNwZixfahRqyhKNkZ4w== X-Google-Smtp-Source: AGHT+IFESUDnoxkBRGGFEsil5vwwqQnr0M2E/rzO5Ah3pXUbKQzjO+St/IUq3wX79za0eMMedUk/mMc= X-Received: from xur.c.googlers.com ([fda3:e722:ac3:cc00:20:ed76:c0a8:2330]) (user=xur job=sendgmr) by 2002:a5b:94c:0:b0:e28:ef8f:7424 with SMTP id 3f1490d57ef6-e28fe44d418mr60122276.11.1728588254050; Thu, 10 Oct 2024 12:24:14 -0700 (PDT) Date: Thu, 10 Oct 2024 12:23:57 -0700 In-Reply-To: <20241010192400.451187-1-xur@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20241010192400.451187-1-xur@google.com> X-Mailer: git-send-email 2.47.0.rc1.288.g06298d1525-goog Message-ID: <20241010192400.451187-6-xur@google.com> Subject: [PATCH v3 5/6] AutoFDO: Enable machine function split optimization for AutoFDO From: Rong Xu To: Alice Ryhl , Andrew Morton , Arnd Bergmann , Bill Wendling , Borislav Petkov , Breno Leitao , Brian Gerst , Dave Hansen , David Li , Han Shen , Heiko Carstens , "H. Peter Anvin" , Ingo Molnar , Jann Horn , Jonathan Corbet , Josh Poimboeuf , Juergen Gross , Justin Stitt , Kees Cook , Masahiro Yamada , "Mike Rapoport (IBM)" , Nathan Chancellor , Nick Desaulniers , Nicolas Schier , "Paul E. McKenney" , Peter Zijlstra , Rong Xu , Sami Tolvanen , Thomas Gleixner , Wei Yang , workflows@vger.kernel.org, Miguel Ojeda , Maksim Panchenko Cc: x86@kernel.org, linux-arch@vger.kernel.org, linux-doc@vger.kernel.org, linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, llvm@lists.linux.dev, Sriraman Tallam , Krzysztof Pszeniczny Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Enable the machine function split optimization for AutoFDO in Clang. Machine function split (MFS) is a pass in the Clang compiler that splits a function into hot and cold parts. The linker groups all cold blocks across functions together. This decreases hot code fragmentation and improves iCache and iTLB utilization. MFS requires a profile so this is enabled only for the AutoFDO builds. Co-developed-by: Han Shen Signed-off-by: Han Shen Signed-off-by: Rong Xu Suggested-by: Sriraman Tallam Suggested-by: Krzysztof Pszeniczny --- include/asm-generic/vmlinux.lds.h | 6 ++++++ scripts/Makefile.autofdo | 2 ++ 2 files changed, 8 insertions(+) diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinu= x.lds.h index ace617d1af9b..20e46c0917db 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -565,9 +565,14 @@ defined(CONFIG_AUTOFDO_CLANG) __unlikely_text_start =3D .; \ *(.text.unlikely .text.unlikely.*) \ __unlikely_text_end =3D .; +#define TEXT_SPLIT \ + __split_text_start =3D .; \ + *(.text.split .text.split.[0-9a-zA-Z_]*) \ + __split_text_end =3D .; #else #define TEXT_HOT *(.text.hot .text.hot.*) #define TEXT_UNLIKELY *(.text.unlikely .text.unlikely.*) +#define TEXT_SPLIT #endif =20 /* @@ -584,6 +589,7 @@ defined(CONFIG_AUTOFDO_CLANG) ALIGN_FUNCTION(); \ *(.text.asan.* .text.tsan.*) \ *(.text.unknown .text.unknown.*) \ + TEXT_SPLIT \ TEXT_UNLIKELY \ . =3D ALIGN(PAGE_SIZE); \ TEXT_HOT \ diff --git a/scripts/Makefile.autofdo b/scripts/Makefile.autofdo index 9c9a530ef090..380042a301cc 100644 --- a/scripts/Makefile.autofdo +++ b/scripts/Makefile.autofdo @@ -11,6 +11,7 @@ endif =20 ifdef CLANG_AUTOFDO_PROFILE CFLAGS_AUTOFDO_CLANG +=3D -fprofile-sample-use=3D$(CLANG_AUTOFDO_PROFILE= ) -ffunction-sections + CFLAGS_AUTOFDO_CLANG +=3D -fsplit-machine-functions endif =20 ifdef CONFIG_LTO_CLANG_THIN @@ -18,6 +19,7 @@ ifdef CONFIG_LTO_CLANG_THIN KBUILD_LDFLAGS +=3D --lto-sample-profile=3D$(CLANG_AUTOFDO_PROFILE) endif KBUILD_LDFLAGS +=3D --mllvm=3D-enable-fs-discriminator=3Dtrue --mllvm=3D= -improved-fs-discriminator=3Dtrue -plugin-opt=3Dthinlto + KBUILD_LDFLAGS +=3D -plugin-opt=3D-split-machine-functions endif =20 export CFLAGS_AUTOFDO_CLANG --=20 2.47.0.rc1.288.g06298d1525-goog