From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from fra-out-001.esa.eu-central-1.outbound.mail-perimeter.amazon.com (fra-out-001.esa.eu-central-1.outbound.mail-perimeter.amazon.com [18.156.205.64]) (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 80848346E72 for ; Fri, 30 Jan 2026 16:13:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=18.156.205.64 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769789600; cv=none; b=XAD6jYgXFFWG+BtMvVjpVc8N15pW0rFfXX5KbXD20XzGnwnnDVOHPR6L3c690K6JHf+oqwoQ/k5Kazh/ef61dWEgBVZEEpqG4m2uBpM+NFL+9wBvziE4M9LjMZUxa5xKOxlp4q7BcWbaPX1Rkz/Xo7eQLKHrOzG4UMIrFcmMyoE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769789600; c=relaxed/simple; bh=ElG5B7QYBFoY+MP3bubh0SfulAy42J/417mZxN7aSE8=; h=Subject:Message-ID:Date:MIME-Version:To:CC:References:From: In-Reply-To:Content-Type; b=HdK8pvFTalicXL5pXo7b2LPDzdCXWwFhOgPQmO4rWN5V4LFachvMs9YQWWYrhZSl92f7H/CJV7k3SiGRDjtpeJIGPjEBCqmP52zpYkISYm2TkEmaOp1xUBckJ2pKNSWpqRJbmAr2iWgsiuKNk931GoA9G3EBA+hv537TtyhemU8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amazon.com; spf=pass smtp.mailfrom=amazon.com; dkim=pass (2048-bit key) header.d=amazon.com header.i=@amazon.com header.b=qmcrG6H0; arc=none smtp.client-ip=18.156.205.64 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amazon.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=amazon.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=amazon.com header.i=@amazon.com header.b="qmcrG6H0" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazoncorp2; t=1769789598; x=1801325598; h=message-id:date:mime-version:to:cc:references:from: in-reply-to:content-transfer-encoding:subject; bh=5r1aDe7D5unqNJNiO+wl91TCGHiQXGLJ/T1n+7taeiM=; b=qmcrG6H04C/KHi0b8BhWMM+NioEkQ9kxG7th31DKDeP0jh9LpHpTkH5+ 5Yj8zyeEJD+k+ZLkv7vlPjx8d6Xn+2xbAVpzOJjWNr4t63+tLwl3iKW5S dc9X8ZHSPkXkbWstCSBSi7eiuBKeUIBf5klfAFNNIYl6sXvZmQ+eMCMKH yYRE8sfpLs6IhPQ2uylABs/hGwdR/6aCcjtlTiu3v5Y7YA2Rgma4hwadu TX9XxHKSPybTpKjX5maJjBd6q3dY3IZzEhem5CEWo5qZRkBgcFnRXOghA WBr2uKHwz8obn/FNd7Riiqw35qvxEqZdYbWnD6IMcV1QS8MjDANKBvVRb Q==; X-CSE-ConnectionGUID: yGkD19vkQKWdX3jeCr+ufw== X-CSE-MsgGUID: 6dGa2FN3TxeQVb+Q2YT/8w== X-IronPort-AV: E=Sophos;i="6.21,263,1763424000"; d="scan'208";a="8356359" Subject: Re: [PATCH 4/4] sched/fair: Proportional newidle balance Received: from ip-10-6-11-83.eu-central-1.compute.internal (HELO smtpout.naws.eu-central-1.prod.farcaster.email.amazon.dev) ([10.6.11.83]) by internal-fra-out-001.esa.eu-central-1.outbound.mail-perimeter.amazon.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 30 Jan 2026 16:12:54 +0000 Received: from EX19MTAEUC001.ant.amazon.com [54.240.197.225:11546] by smtpin.naws.eu-central-1.prod.farcaster.email.amazon.dev [10.0.23.244:2525] with esmtp (Farcaster) id fa0618b7-0c30-4b06-8e7e-cd90f94d3e23; Fri, 30 Jan 2026 16:12:54 +0000 (UTC) X-Farcaster-Flow-ID: fa0618b7-0c30-4b06-8e7e-cd90f94d3e23 Received: from EX19D018EUA004.ant.amazon.com (10.252.50.85) by EX19MTAEUC001.ant.amazon.com (10.252.51.155) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.2562.35; Fri, 30 Jan 2026 16:12:54 +0000 Received: from [192.168.18.115] (10.106.82.24) by EX19D018EUA004.ant.amazon.com (10.252.50.85) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.2562.35; Fri, 30 Jan 2026 16:12:53 +0000 Message-ID: <55e55d11-22a7-450d-9ad2-dbf958b904a6@amazon.com> Date: Fri, 30 Jan 2026 16:12:52 +0000 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird To: Peter Zijlstra CC: Mario Roy , Chris Mason , "Joseph Salisbury" , Adam Li , Josh Don , , , , , , , , , References: <20251107160645.929564468@infradead.org> <20251107161739.770122091@infradead.org> <8760001e-0274-454c-a4e4-1f38a9695b88@gmail.com> <3ef2a178-db96-4a2c-9e74-44ba81bef030@amazon.com> <20260127084412.GV171111@noisy.programming.kicks-ass.net> <20260129091937.GY166857@noisy.programming.kicks-ass.net> <20260129092408.GE217302@noisy.programming.kicks-ass.net> Content-Language: en-US From: "Mohamed Abuelfotoh, Hazem" In-Reply-To: <20260129092408.GE217302@noisy.programming.kicks-ass.net> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit X-ClientProxiedBy: EX19D015EUA001.ant.amazon.com (10.252.50.229) To EX19D018EUA004.ant.amazon.com (10.252.50.85) On 29/01/2026 09:24, Peter Zijlstra wrote: > CAUTION: This email originated from outside of the organization. Do not click links or open attachments unless you can confirm the sender and know the content is safe. > > > > On Thu, Jan 29, 2026 at 10:19:37AM +0100, Peter Zijlstra wrote: >> On Wed, Jan 28, 2026 at 03:48:13PM +0000, Mohamed Abuelfotoh, Hazem wrote: >> >>> Below are the hardware specs for both c7i.4xlarge & c7a.4xlarge. >>> >>> c7i.4xlarge >>> >>> CPU Model: Intel(R) Xeon(R) Platinum 8488C >>> Number of CPUs: 16 >>> Memory: 32 GB >>> Number of sockets: 1 >> >> But the 8488C is a 56 core part, with 112 threads. So you're handing out >> 8 core partitions of that thing, for 7 such instances on one machine? >> >> (Also, calling anything 16 core with 32GB 'large' is laughable, that's >> laptop territory.) > > Also, are you employing Intel-CAT on these partitions to separate the > L3s? > > (Not immediately relevant I suppose, but I was curious) > We don't enable Intel-CAT to partition L3 cache between VMs.