From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 EFE3C14A614 for ; Tue, 18 Feb 2025 08:30:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.137.202.133 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739867462; cv=none; b=mwueaNVSIwMGiE27V8eNA8ycA75vimv42irXDIIoZPgWCynvXRfY0Klz/NF9uzmv4aCHfEfZaks5oS6xiPBk+lUDV4SS5YUTwSRSsJK3kIPc9QXWXgP9RMH6N0RvciBdS0zmJ6DlzxOB8RBaMI7OUgvqBMUIfrFi6RfZNTNWyt8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739867462; c=relaxed/simple; bh=9VtGtvfK+7UzennBQPH/y8QET6S4ivcT3jIgw948x2w=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=SotVARPD8xM3thV+3xpsxB4Xpo2BULOuPn0EL93Tt6aP0CU13IwzEHr10shWKJ2VEUvlNN6LnSscAT2KhQhfbjhOJLDc6nk3jSUzAaIPMs0VcDp4RT/IpLqbKdZiKZXQsViENgt8p93njfciL4BVCrNKpO5MpS11BYLFagsNKu0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=Ft+YSrGL; arc=none smtp.client-ip=198.137.202.133 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="Ft+YSrGL" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=In-Reply-To:Content-Transfer-Encoding :Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date: Sender:Reply-To:Content-ID:Content-Description; bh=yOTi56SfhhNFwDe4d/KIll5p8ktrPz80A3kxdYRZp/c=; b=Ft+YSrGLOphknqITOuLEzPx47O YTwUWx8RlDw6aphRneoX5VgYQxblMA8TxZQAiLI4J7nip25xQfydQIX2+21x+Jw4pJCKDie0pOuhd J2+S5secjUFGm2EyyLFVptS5csbx+j6zEiPhtkQbcPtuQ4degWhlRvtOpl1e6/jhlDfH5FDpul1Ua ngBQDqpGotWTb0fHNEVD2//2tpBKkv3OM8A7VQjLcietMlE9813KuFMgDK1qtyNu6eZkaw43NB0n8 wrf9aLCBCY1xrY1DOA7tFH4dEKyIDe8GtUWCL1XQcMNIJZaO4OUkwlMpFhvgjbqtrv+b7Y+0tEDIH K1abrh0Q==; Received: from hch by bombadil.infradead.org with local (Exim 4.98 #2 (Red Hat Linux)) id 1tkJ0L-00000007ILX-0aTn; Tue, 18 Feb 2025 08:30:57 +0000 Date: Tue, 18 Feb 2025 00:30:57 -0800 From: Christoph Hellwig To: Daniel Gomez Cc: Christoph Hellwig , linux-xfs@vger.kernel.org, Luis Chamberlain , Daniel Gomez , Pankaj Raghav , gost.dev@samsung.com Subject: Re: [PATCH] mkfs: use stx_blksize for dev block size by default Message-ID: References: <20250206-min-io-default-blocksize-v1-1-2312e0bb8809@samsung.com> <323gt6bngrysa3i6nzgih6golhs3wovawnn5chjcrkegajinw7@fxdjlji5xbxb> Precedence: bulk X-Mailing-List: linux-xfs@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: X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html On Thu, Feb 13, 2025 at 02:26:37PM +0100, Daniel Gomez wrote: > That's a good question. The stx_blksize field description indicates the value > should be referring to the fs block size that avoids RMW. One that is optimal, the RMW is an example. This what Posix says: blksize_t st_blksize A file system-specific preferred I/O block size for this object. In some file system types, this may vary from file to file. > So I think, if devices report high values in stx_blksize, it is either because > smaller values than the reported one cause RMW or they are incorrectly reporting > a value in the wrong statx field. Or it is just more efficient. E.g. on NFS or XFS you'll get fairly big values. > The commit I refer in the commit message maps the minimum_io_size reported by > the block layer with stx_blksize. Yes, and that was my question again - minimum_io_size for block devices is specified even more handwavy. In other words I'm really sceptical this is going to be a net win. To win me over you'll need to show a improvement over a wide variety of devіces and workloads.