From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5D4F114AD24; Mon, 9 Dec 2024 16:20:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733761235; cv=none; b=YUCNEGLb/+3utIn7mBjr1tp5ogse96vRw/f6hPNs/Z/L+46PqbhCpH251fkhbyb+ESyz4rMeUxR9VXn2r81AXNGLU/ltYB5MDsXBEK2KrfDxm5UH8HQnSkMlfbfIqQdtfcBtFg5b9/qNCjtktErQEqSXC2aFotSdgeMf71Htrfo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733761235; c=relaxed/simple; bh=A0khTX962w4Lj2UZnP6iKvULYKO5dZNtoX7UeansjzE=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=twpdzAU6KcleW6r1U8rAi5ZpFg/0qFXiAjyD2xtCVXUfvgKG0706WnQfD0/1ywpsD5pjrRlP3QjZ+Eb7LoWczszYNbhMBYnRbQXpjPxammDrVJobwulR6hfzz5HNy77vSgzWjGjd4JJjblD3NX98dmGaIQU6cHfEE+CL+uYLmVE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=uK+HxU+7; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="uK+HxU+7" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B0C7FC4CEDE; Mon, 9 Dec 2024 16:20:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1733761235; bh=A0khTX962w4Lj2UZnP6iKvULYKO5dZNtoX7UeansjzE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=uK+HxU+7UrafZWQAtX1yFKqLzr3GhtOoQ/I9qjhOXe6jTLtmtJJG3KeIfN+pCl52V SuXy7P2d/WL1Ss8nzRAEHSimrk2PUmzwp7X26037XpdcMPYvmkYnE+sHgTIZsKrUK4 U9WyfTktZYBoew26+tTqWCm5l9AYXYCGHqzGRRGKntCtlMy3M+waCF9Y3y9LNbokf/ q6mQufLiMJrwhcZwa6S/tanQ6e/8jGJvZ54xMfKyei1YgNOLdvanuL4NyminJoySiF InqCHHwsyavoTXPiTXjGvEClQPvgvlbr9uJ6SsQ+FWCXJ6saHAT+Aavv2twnJoGIbv t9dq4WzA85JYg== Date: Mon, 9 Dec 2024 16:20:29 +0000 From: Will Deacon To: Yabin Cui Cc: Rong Xu , Han Shen , Jonathan Corbet , Catalin Marinas , Masahiro Yamada , Kees Cook , Nick Desaulniers , workflows@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH v2] arm64: Allow CONFIG_AUTOFDO_CLANG to be selected Message-ID: <20241209162028.GD12428@willie-the-truck> References: <20241118222540.27495-1-yabinc@google.com> Precedence: bulk X-Mailing-List: workflows@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20241118222540.27495-1-yabinc@google.com> User-Agent: Mutt/1.10.1 (2018-07-13) On Mon, Nov 18, 2024 at 02:25:40PM -0800, Yabin Cui wrote: > Select ARCH_SUPPORTS_AUTOFDO_CLANG to allow AUTOFDO_CLANG to be > selected. > > On ARM64, ETM traces can be recorded and converted to AutoFDO profiles. > Experiments on Android show 4% improvement in cold app startup time > and 13% improvement in binder benchmarks. > > Signed-off-by: Yabin Cui > --- > > Change-Logs in V2: > > 1. Use "For ARM platforms with ETM trace" in autofdo.rst. > 2. Create an issue and a change to use extbinary format in instructions: > https://github.com/Linaro/OpenCSD/issues/65 > https://android-review.googlesource.com/c/platform/system/extras/+/3362107 > > Documentation/dev-tools/autofdo.rst | 18 +++++++++++++++++- > arch/arm64/Kconfig | 1 + > 2 files changed, 18 insertions(+), 1 deletion(-) > > diff --git a/Documentation/dev-tools/autofdo.rst b/Documentation/dev-tools/autofdo.rst > index 1f0a451e9ccd..a890e84a2fdd 100644 > --- a/Documentation/dev-tools/autofdo.rst > +++ b/Documentation/dev-tools/autofdo.rst > @@ -55,7 +55,7 @@ process consists of the following steps: > workload to gather execution frequency data. This data is > collected using hardware sampling, via perf. AutoFDO is most > effective on platforms supporting advanced PMU features like > - LBR on Intel machines. > + LBR on Intel machines, ETM traces on ARM machines. > > #. AutoFDO profile generation: Perf output file is converted to > the AutoFDO profile via offline tools. > @@ -141,6 +141,22 @@ Here is an example workflow for AutoFDO kernel: > > $ perf record --pfm-events RETIRED_TAKEN_BRANCH_INSTRUCTIONS:k -a -N -b -c -o -- > > + - For ARM platforms with ETM trace: > + > + Follow the instructions in the `Linaro OpenCSD document > + https://github.com/Linaro/OpenCSD/blob/master/decoder/tests/auto-fdo/autofdo.md`_ > + to record ETM traces for AutoFDO:: > + > + $ perf record -e cs_etm/@tmc_etr0/k -a -o -- > + $ perf inject -i -o --itrace=i500009il > + > + For ARM platforms running Android, follow the instructions in the > + `Android simpleperf document > + `_ > + to record ETM traces for AutoFDO:: > + > + $ simpleperf record -e cs-etm:k -a -o -- > + > 4) (Optional) Download the raw perf file to the host machine. > > 5) To generate an AutoFDO profile, two offline tools are available: > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > index fd9df6dcc593..c3814df5e391 100644 > --- a/arch/arm64/Kconfig > +++ b/arch/arm64/Kconfig > @@ -103,6 +103,7 @@ config ARM64 > select ARCH_SUPPORTS_PER_VMA_LOCK > select ARCH_SUPPORTS_HUGE_PFNMAP if TRANSPARENT_HUGEPAGE > select ARCH_SUPPORTS_RT > + select ARCH_SUPPORTS_AUTOFDO_CLANG > select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH > select ARCH_WANT_COMPAT_IPC_PARSE_VERSION if COMPAT > select ARCH_WANT_DEFAULT_BPF_JIT After this change, both arm64 and x86 select this option unconditionally and with no apparent support code being added. So what is actually required in order to select ARCH_SUPPORTS_AUTOFDO_CLANG and why isn't it just available for all architectures instead? Will