From nobody Sun Feb 8 19:24:26 2026 Received: from fanzine2.igalia.com (fanzine2.igalia.com [213.97.179.56]) (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 2376655E70; Sat, 3 Feb 2024 15:22:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=213.97.179.56 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706973749; cv=none; b=E5Qgh8NzYDx979b5S4WbxirX9atL2W2ibnu4iU4AYveYoUDBs1cg1kJTLg3sB1dHXOLgOmAFkmqMlc/Cc/2os4joimuidTIaC61217iAIoXJr0v5rZt+V3FjqNLhHS1G5CfBHyBo67r62SGAFHzLHcK2r4kF16Fyua1wuHSF7AE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706973749; c=relaxed/simple; bh=c+Jc4BAS+IryDupflpvWK9nQ/pkuVv+Flzsyr7rEEDw=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=t19uylTRv/yNx35kajZ4VaP7jhRNOVQbzG5dBI29XyWPT0bcuW00k2cF9yw2TWxwRuP38OIB7J8QAEGXJWqG3NemqLKUNn6xYhyhNsrWXAm9ay8/1Ls56gXNzEoEgq3LrxAYKgAq39+K9FhBvBK9fjX/wLkuv/m6J9YYFlVBQvs= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=igalia.com; spf=pass smtp.mailfrom=igalia.com; dkim=pass (2048-bit key) header.d=igalia.com header.i=@igalia.com header.b=QGqG24Wv; arc=none smtp.client-ip=213.97.179.56 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=igalia.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=igalia.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=igalia.com header.i=@igalia.com header.b="QGqG24Wv" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=Content-Transfer-Encoding:MIME-Version:Message-ID:Date:Subject: Cc:To:From:Sender:Reply-To:Content-Type:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: In-Reply-To:References:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=j9K/vax56e3sCnb71UIU5Gz4B8feV2qAX5/Vur9/dM8=; b=QGqG24WvpulgcmjYWeP8Fzj7U/ IDQyV210c3AwnZgQSuytBZ8xpVsTGWSJ7OKnfCWF6MzQD65aautSRsr4vcTcPBP1lnF1s9HZ2yg5W veng2shFrLwq4KM5wmQ4c5HY1YQV3z4cEmzp5IGQv9rxhOHMjaXeKHUaAnUh84TLin29RxETU+W3Q V7jDq/T41zpRwMhWr/6RiucZo5uZXV3x9Lw29Wx63CkLQifvwWH9Df5cct3cZ19CrUxRKBpAnDsAj QnmnmrAMxGPnQ+pz8gO65O5q22jYQ9bGzBvISh11tdCpVn+PrKwTuoBlnmDx3goLsIWj8HWmu5bXt ztzRv2CQ==; Received: from [187.90.178.235] (helo=localhost) by fanzine2.igalia.com with esmtpsa (Cipher TLS1.3:ECDHE_SECP256R1__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim) id 1rWHqP-00DJoe-Vg; Sat, 03 Feb 2024 16:22:14 +0100 From: "Guilherme G. Piccoli" To: linux-doc@vger.kernel.org, corbet@lwn.net Cc: linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, rdunlap@infradead.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, hca@linux.ibm.com, gor@linux.ibm.com, agordeev@linux.ibm.com, borntraeger@linux.ibm.com, svens@linux.ibm.com, kernel@gpiccoli.net, kernel-dev@igalia.com, "Guilherme G. Piccoli" , Changwoo Min Subject: [PATCH] docs: Document possible_cpus parameter Date: Sat, 3 Feb 2024 12:21:13 -0300 Message-ID: <20240203152208.1461293-1-gpiccoli@igalia.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" The number of possible CPUs is set be kernel in early boot time through some discovery mechanisms, like ACPI in x86. We have a parameter both in x86 and S390 to override that - there are some cases of BIOSes exposing more possible CPUs than the available ones, so this parameter is a good testing mechanism, but for some reason wasn't mentioned so far in the kernel parameters guide - let's fix that. Cc: Changwoo Min Signed-off-by: Guilherme G. Piccoli Reviewed-by: Randy Dunlap --- Documentation/admin-guide/kernel-parameters.txt | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentatio= n/admin-guide/kernel-parameters.txt index 31b3a25680d0..e553740190ea 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -4644,6 +4644,11 @@ may be specified. Format: ,.... =20 + possible_cpus=3D [SMP,S390,X86] + Format: + Set the number of possible CPUs, overriding the + regular discovery mechanisms (such as ACPI/FW, etc). + powersave=3Doff [PPC] This option disables power saving features. It specifically disables cpuidle and sets the platform machine description specific power_save --=20 2.43.0