From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from submarine.notk.org (62-210-214-84.rev.poneytelecom.eu [62.210.214.84]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 75AE17829C; Tue, 2 Jul 2024 08:20:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=62.210.214.84 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719908464; cv=none; b=PgB8anPtpk3WLeE2bcS5y0LmiT+9oZDQll3PffPxdj0l/G4J4LPfDy/GxPu38hdFiLCW2OjmnwIymTC44AEHYXDTcB413ns5d0aqDLf0YMtweqOJOiKgCf1SMp73g5Laozs8Ow/Em+quhZydQK7uBtvZkCvwCF8Ik9IY6BHBllo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719908464; c=relaxed/simple; bh=ltTU1jjpksscy88CQUgovGBPuuFSNhvY+R52IMfM6TQ=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=EdbTWC8zBSDe8CThQ45UhtHwdbxZCiNk4xJolgwhlbh6YOcCf0w9UqBaFzUJzNDG4a3JGpSPYNA1tJhsr8dut34NQV7Xcds3HN3NMNxfb1rXKZX6NObamIhJCE4rX4Vl4dHfJy0tLkJsuJWmtF71pqTW3TykkkgBy/rPk7v25i8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=codewreck.org; spf=pass smtp.mailfrom=codewreck.org; dkim=pass (2048-bit key) header.d=codewreck.org header.i=@codewreck.org header.b=jjPi2tWi; arc=none smtp.client-ip=62.210.214.84 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=codewreck.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=codewreck.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=codewreck.org header.i=@codewreck.org header.b="jjPi2tWi" Received: from gaia.codewreck.org (localhost [127.0.0.1]) by submarine.notk.org (Postfix) with ESMTPS id A827814C1E1; Tue, 2 Jul 2024 10:20:51 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=codewreck.org; s=2; t=1719908456; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=lKlB2Lo1Tj0ZL4kVYWbn12m4jdB0MZvffzHvvLvzLug=; b=jjPi2tWipzIa94/BBeRCwRPtN9Y8OGE9ngz8cF44Xa1IJLDy2Fm+0S+BxZa4cHrXLm5+sX sAOLlswOXorzRes6JggC2daiBdouDbJDymVPsPujDxb4CAZehTwtDSe31/GfAMDsF+UUAy bI3XsW/LdqgtR2mLQ15kTUwWTu2vKqZJ5k6b3Ok2PzRcB+c88RdXUI+MQI+JLPPNndkWxD V3Ny8olqYHpEj5kR0+zJeppln9B4+97/Mwvrmxvf6BB2wwO2KspcUI0uJns79lVXpIDYtC sn4T0zGCgY9bu9Y2EzzIVksTz8qYnixkWECgXEyiJJKVTrCmZVFMLrJxACGpfA== Received: from localhost (gaia.codewreck.org [local]) by gaia.codewreck.org (OpenSMTPD) with ESMTPA id 737de09b; Tue, 2 Jul 2024 08:20:46 +0000 (UTC) Date: Tue, 2 Jul 2024 17:20:31 +0900 From: asmadeus@codewreck.org To: Masahiro Yamada Cc: Alan Maguire , ast@kernel.org, andrii@kernel.org, daniel@iogearbox.net, nathan@kernel.org, nicolas@fjasle.eu, martin.lau@linux.dev, eddyz87@gmail.com, song@kernel.org, yonghong.song@linux.dev, john.fastabend@gmail.com, kpsingh@kernel.org, sdf@google.com, haoluo@google.com, jolsa@kernel.org, bpf@vger.kernel.org, linux-kbuild@vger.kernel.org Subject: Re: [PATCH bpf-next] kbuild, bpf: reproducible BTF from pahole when KBUILD_BUILD_TIMESTAMP set Message-ID: References: <20240701173133.3283312-1-alan.maguire@oracle.com> Precedence: bulk X-Mailing-List: linux-kbuild@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Masahiro Yamada wrote on Tue, Jul 02, 2024 at 04:58:50PM +0900: > If --btf_features=reproducible_build has no downside, > please add it whenever supported. It makes the build slightly slower (from [1], 3.858 -> 3.991 (+3%) on my crippled machine for the vmlinux BTF phase -- the modules also get similar treatment, I'm not sure how big the total time exactly is -- for large kernels with tons of modules it definitely adds up but for small kernels it's probably "short enough") [1] https://lkml.kernel.org/r/20240626032253.3406460-1-asmadeus@codewreck.org I don't particularly mind either way, so this is mostly out of curiosity: do we have any other setting that would be closer better than this KBUILD_BUILD_TIMESTAMP to say "make this reproducible", or is the kernel build supposed to be reproducible except for the date by default? Thank you, -- Dominique Martinet | Asmadeus