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 A95721A2C3A for ; Fri, 10 May 2024 16:20:05 +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=1715358005; cv=none; b=msVXS9hCYCz6n2o2Iiv0naPahHyhRSz/d53SQ7SRppbyrE5No6HodWCbMaS5zDxjn98MndvX/VmXgeca3WVL3OkkAd+qTReyOJVpv1tQfTT45p1Lfo4Pjj5Ya9ugdQ9aaOBUV5rNzWaUUuzGvfss3x1TOViF5NRQIfKhKi9ZnOQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715358005; c=relaxed/simple; bh=CF8Nf3rfqr2ncS/J0xp4oHnRS2E3OUw0FJDGJKNSq/0=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=AtVWwgp57ICC5g4jxZU3mU69gdNPDLDSk6hFbiWFDRoMSZhiYpGbZ81dZM/LyinuuI7f/bSvj47qy2VSYdTyG1qVftEJUPEWgIMKhiUGcZB+XAEP5Nu2S8sbhmLmatKM9ZyGqzc9EcZZKdgH6JnIErzA2q+dRZLV+U/ChoWD8vo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=LnNrBJye; 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="LnNrBJye" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B721BC113CC; Fri, 10 May 2024 16:20:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1715358005; bh=CF8Nf3rfqr2ncS/J0xp4oHnRS2E3OUw0FJDGJKNSq/0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=LnNrBJye4r8wFkX4YaHhnzSf6Bj+yeERi0onolrcgAKGavgSIbw4SjvRooP+Gzpw2 kd8BTX6RWWVo6C1cKeItxfFCxv7hXCfNbBOHxXhCJoYUftI1PtScLxHkaEGVGmqRLB c5fPQHLIK55ILI+j177+w+GYhYi+lz83hB1i8gRTVQtGLqtB1MoDjDdmWYLYtl9uod eSrZpLTWE/33O3xd5dusWN4o+GtwsFPu6UyULIz9RvPQp3ltTPxn5n8NLiC5F0/AO2 1NEoqh1VnO+SubjSRRkSAfH8iX364gA9mhoDibbx6pZc+AUti2p3c6chKQ5XfzUxXF QUqlw+bE2Ul7g== Date: Fri, 10 May 2024 10:20:02 -0600 From: Keith Busch To: Christoph Hellwig Cc: Keith Busch , linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org, tglx@linutronix.de, ming.lei@redhat.com Subject: Re: [PATCH 2/2] nvme-pci: allow unmanaged interrupts Message-ID: References: <20240510141459.3207725-1-kbusch@meta.com> <20240510141459.3207725-2-kbusch@meta.com> <20240510151047.GA10486@lst.de> 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 Content-Disposition: inline In-Reply-To: <20240510151047.GA10486@lst.de> On Fri, May 10, 2024 at 05:10:47PM +0200, Christoph Hellwig wrote: > On Fri, May 10, 2024 at 07:14:59AM -0700, Keith Busch wrote: > > From: Keith Busch > > > > Some people _really_ want to control their interrupt affinity. > > So let them argue why. I'd rather have a really, really, really > good argument for this crap, and I'd like to hear it from the horses > mouth. It's just prioritizing predictable user task scheduling for a subset of CPUs instead of having consistently better storage performance. We already have "isolcpus=managed_irq," parameter to prevent managed interrupts from running on a subset of CPUs, so the use case is already kind of supported. The problem with that parameter is it is a no-op if the starting affinity spread contains only isolated CPUs.