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 A59C4193417; Thu, 31 Oct 2024 14:06:27 +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=1730383588; cv=none; b=QFok1N9uEH63W8BOedWs48M0URNHZkg0g4XrCtulkFLBTUrbNiMMZVJ5AsIrFo3QJxIW7a/uYnMJMU0rOqJgdU5FHlM/X4RWV1Mcu7h2Lij1WrFrfsNTANUFH3jGupUsgcxKr1sqh3YdWargg93QmBOCx81zP75enYJF/E4q6L8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730383588; c=relaxed/simple; bh=Muuu1WqyPpcP/xIjgoC6z8E8xeJtiugg598fNvNyN/E=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=MV0JT534Z8tT/kKfSRwpll1urMPbU/GeWwjQ7sVtkB2kITQpEhqxOryUOVejsbDPpfJcdup5gjYxkaw5smn6xuxdcuF+vO4n+EM734wWyopJCQpDpUN3d8y1OeTG3CvClJDgIBMdzM3WlVJv7yDeWt16u4NFzRR9U4tWOrSAoFg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Yajt8S6A; 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="Yajt8S6A" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 97E5CC4FF52; Thu, 31 Oct 2024 14:06:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1730383587; bh=Muuu1WqyPpcP/xIjgoC6z8E8xeJtiugg598fNvNyN/E=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Yajt8S6AC7lJXMJrgMLEU3WjiH6d4vU7KU0GM5nIxrxzkAw/O57yMJU7wWVVXTkNR rY7sX5J9AIFrLXPtjGtoazojQ9YMoRazK6YBgLm/ELf+L+vJloJIS1QHBNTvOQnyzK /l78HsUM4nNyzQrlqs8HL8HhaIy5TS1lfMc4hSDpq69PpZOzCBGlWoXYC+1wImnmbN 1YmgKCBdtkdZ+PXXHKzy4NmGvZwLiLJ9w0WFhqCqoV1tjb6rO1Inv5xcZOPlxoYUIG SxWpP4CQAvW8UfWHyswYpaL0doLT2p3x8cHDslxjtZ6pL2ZtNVyfw6FDnII5RTIBDO OiNIopie+Riww== Date: Thu, 31 Oct 2024 08:06:24 -0600 From: Keith Busch To: Hans Holmberg Cc: Christoph Hellwig , Keith Busch , linux-block@vger.kernel.org, linux-nvme@lists.infradead.org, linux-scsi@vger.kernel.org, io-uring@vger.kernel.org, linux-fsdevel@vger.kernel.org, joshi.k@samsung.com, javier.gonz@samsung.com, bvanassche@acm.org, Hannes Reinecke Subject: Re: [PATCHv10 9/9] scsi: set permanent stream count in block limits Message-ID: References: <20241030045526.GA32385@lst.de> <20241030154556.GA4449@lst.de> <20241030155052.GA4984@lst.de> <20241030165708.GA11009@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=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: On Thu, Oct 31, 2024 at 09:19:51AM +0100, Hans Holmberg wrote: > On Wed, Oct 30, 2024 at 11:33 PM Keith Busch wrote: > > That is very much apples-to-oranges. The B+ isn't on the same device > > being evaluated for WAF, where this has all that mixed in. I think the > > results are pretty good, all things considered. > > No. The meta data IO is just 0.1% of all writes, so that we use a > separate device for that in the benchmark really does not matter. It's very little spatially, but they overwrite differently than other data, creating many small holes in large erase blocks. > Since we can achieve a WAF of ~1 for RocksDB on flash, why should we > be content with another 67% of unwanted device side writes on top of > that? > > It's of course impossible to compare your benchmark figures and mine > directly since we are using different devices, but hey, we definitely > have an opportunity here to make significant gains for FDP if we just > provide the right kernel interfaces. > > Why shouldn't we expose the hardware in a way that enables the users > to make the most out of it? Because the people using this want this interface. Stalling for the last 6 months hasn't produced anything better, appealing to non-existent vaporware to block something ready-to-go that satisfies a need right now is just wasting everyone's time. Again, I absolutely disagree that this locks anyone in to anything. That's an overly dramatic excuse.