From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from gentwo.org (gentwo.org [62.72.0.81]) (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 E28ED2E8E12 for ; Mon, 8 Sep 2025 15:25:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=62.72.0.81 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757345157; cv=none; b=pnq9/0aosENkynncG29YLESrrFmT6+nDdZM8+VHf8P0bDBKlfQp1ha/kl8XdlYvm+zvYpR16MMR9K9Wl5Pm2yPsc2nMjxK0EFS8QlGVbUC44ynLrGWv3wUbO9lI8GHcX0A58QvC2kavpHjz3zpbDXhdGaV0ETUlOgUI95UrfzKU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757345157; c=relaxed/simple; bh=kKNgUdnpjbd19H18Gsk3GITQ9Z67++kPL7jTcMUjT1Y=; h=Date:From:To:cc:Subject:In-Reply-To:Message-ID:References: MIME-Version:Content-Type; b=sfulYKcLZtpEmp8lkIJhBuo+RZs/AEY4KDII3rsMicGJClMLDSG+HRCwcju9roCYVExsm9WUg9gaueuKiCvEQ79IQSqS2ICDKRjC5mXkkOm/x/T3iP4BJz1viBBCPIoGC2cgyo27lXTYfEG4SIKMFeEmBcev7gKJqsQpHlZ1a3k= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=gentwo.org; spf=pass smtp.mailfrom=gentwo.org; dkim=pass (1024-bit key) header.d=gentwo.org header.i=@gentwo.org header.b=h5PWWhI/; arc=none smtp.client-ip=62.72.0.81 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=gentwo.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gentwo.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=gentwo.org header.i=@gentwo.org header.b="h5PWWhI/" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gentwo.org; s=default; t=1757345148; bh=kKNgUdnpjbd19H18Gsk3GITQ9Z67++kPL7jTcMUjT1Y=; h=Date:From:To:cc:Subject:In-Reply-To:References:From; b=h5PWWhI//okwWzSN9htNz0pCilywJtE0zHgRPyp5HJwv1seYORkVbGWxEwxxBbWdb k7TJrHlhbRA2amPYcxUDjkolyec+6P+izJEIWmNRBsArmn9yhzdpdC6g6apr0v37Ux u6WVQJgzExlV4UBlVb1OQm9PwWStdveeL0DDYQ58= Received: by gentwo.org (Postfix, from userid 1003) id BBD60401E9; Mon, 8 Sep 2025 08:25:48 -0700 (PDT) Received: from localhost (localhost [127.0.0.1]) by gentwo.org (Postfix) with ESMTP id B9D02401DB; Mon, 8 Sep 2025 08:25:48 -0700 (PDT) Date: Mon, 8 Sep 2025 08:25:48 -0700 (PDT) From: "Christoph Lameter (Ampere)" To: Frederic Weisbecker cc: Adam Li , anna-maria@linutronix.de, tglx@linutronix.de, mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, vschneid@redhat.com, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, linux-kernel@vger.kernel.org, patches@amperecomputing.com Subject: Re: [PATCH RESEND 1/2] tick/nohz: Fix wrong NOHZ idle CPU state In-Reply-To: Message-ID: <8fcea325-ca5f-0abd-34e0-1ac7b092e2fb@gentwo.org> References: <20250821042707.62993-1-adamli@os.amperecomputing.com> <20250821042707.62993-2-adamli@os.amperecomputing.com> <6f14ff5c-cddb-f450-b4bb-fcc995b5ce5b@gentwo.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII On Fri, 5 Sep 2025, Frederic Weisbecker wrote: > isolcpus for domain isolation is indeed in the way for long term deprecation > and the only replacement possible is cpuset, which overhead is only visible > on partition creation and update. > > We could argue on the interface, the point is that nohz_full doesn't make sense > without domain isolation. Most use cases I see use nohz_full on all cpus and rely on the OS to exempt the sheperd cpu.