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 CA81C1CEAD6; Fri, 15 Nov 2024 16:28:09 +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=1731688089; cv=none; b=d7KcJBjAK3Nyion77ktXTkD7uY8jgJl7Bg8JXKXVteXPHFsCO+S2tjpqqa2dv9EIj6cPEFlbQ68BOZUEHJla5G6+jGqK6g1fyhctFQyXHwrszTMHedI2j6g8idv0Sdl6UhUtBhfBGhX6Xy/jfyfHH+fuIV450RWHGaqMCa7B2oA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731688089; c=relaxed/simple; bh=XOUgdezN4ZR1SvSwisJLzjliFvPotJwHe9wFvR4ENX8=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=hJFx/7UEXyhuGuPawVrJtDkaEuU5jYYGgrOM91Jbqjnvnwj3ZEpAYsO6dZMnlCrwR0ojNVJTZGyZuJTWLUNRizieW3XOHGBU7YKpHu+GTRLhTCPRkIf9F43WvoQeBCGGGhc6S+KAosWnwdhLE/vLK3HPT989UPbYM6KEkJGxMbw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=RXqZSo45; 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="RXqZSo45" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AA789C4CECF; Fri, 15 Nov 2024 16:28:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1731688089; bh=XOUgdezN4ZR1SvSwisJLzjliFvPotJwHe9wFvR4ENX8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=RXqZSo45vVeTt/JN3nwEBmIhhFCDSMdJ0gFzSXt2LzR+bWzr7z5NDQ/PNKeQVA0hT QHkm3aE4qO44nudL9NZL4aHmVnHQlkh6lDffbKCbMAHAXosypock/hdjoZk9KHFlXO vGKwhpY9gJCiaF+zHU1/bLK8ulxxjEICPa4yKF4hgf1b6wJlPZT2r6YPwJn7+tbfsn ruhVTfUY4jVa6ZNTalNcBjvZOYiyDiRWPhv2zOc3ksqtEWvxiWsciVyv8zKcRhW0R0 kSIsqqgklQ7SupdtgZhCdoxIUFGxtMcy5gQBLJpg0GsRh4hqEH3YJqRRvRvw+ufgOI TY0RCoD7mdmyw== Date: Fri, 15 Nov 2024 09:28:05 -0700 From: Keith Busch To: Christoph Hellwig Cc: Dave Chinner , Pierre Labat , Kanchan Joshi , Keith Busch , "linux-block@vger.kernel.org" , "linux-nvme@lists.infradead.org" , "linux-scsi@vger.kernel.org" , "linux-fsdevel@vger.kernel.org" , "io-uring@vger.kernel.org" , "axboe@kernel.dk" , "martin.petersen@oracle.com" , "asml.silence@gmail.com" , "javier.gonz@samsung.com" Subject: Re: [EXT] Re: [PATCHv11 0/9] write hints with nvme fdp and scsi streams Message-ID: References: <20241108193629.3817619-1-kbusch@meta.com> <20241111102914.GA27870@lst.de> <7a2f6231-bb35-4438-ba50-3f9c4cc9789a@samsung.com> <20241112133439.GA4164@lst.de> <20241113044736.GA20212@lst.de> <20241114060710.GA11169@lst.de> Precedence: bulk X-Mailing-List: io-uring@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: <20241114060710.GA11169@lst.de> On Thu, Nov 14, 2024 at 07:07:10AM +0100, Christoph Hellwig wrote: > On Thu, Nov 14, 2024 at 10:51:09AM +1100, Dave Chinner wrote: > > SGI wrote an entirely new allocator for XFS whose only purpose in > > life is to automatically separate individual streams of user data > > into physically separate regions of LBA space. > > One of the interesting quirks of streams/FDP is that they they operate > on (semi-)physical data placement that is completely decoupled from LBA > space. That's not particularly interesting about FDP. All conventional NAND SSDs operates that way. FDP just reports more stuff because that's what people kept asking for. But it doesn't require you fundamentally change how you acces it. You've singled out FDP to force a sequential write requirement that that requires unique support from every filesystem despite the feature not needing that. We have demonstrated 40% reduction in write amplifcation from doing the most simplist possible thing that doesn't require any filesystem or kernel-user ABI changes at all. You might think that's not significant enough to let people realize those gains without more invasive block stack changes, but you may not buying NAND in bulk if that's the case.