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 E702C2957AD; Wed, 30 Jul 2025 14:14:19 +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=1753884861; cv=none; b=pCNkkDWHW4JFrHb8/oiw29hOS20WXM2NtL47466YQtBywMDWSB4BShx5w0mC4myv0/ZucU37bS2in6IqXUcv4+AYMAxnklgvNiNkV9PfLV6T80hNIXsis8h01IuZgygaMvOIm+qtgQrXRIcv5Iv4+D9sUN4jCf0qfa2FAIQUhT4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753884861; c=relaxed/simple; bh=gwsGzSAGPEXu4CmFH9bM3rRq7cFN49AEUoHzq0yr63c=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=AZl2N97QwxWMSGV8qFMqalEOm3lNxmtEZNnNXbwr/syYql8aP0vzf86oDEbnftKBVguwoCsbEn/ucyQ2EyAAcNzTvGIB4ndZCl5CEdIo2pAc7vQK6awIsiWcm2gk7xJ+g/B3d8YntACR/jMo86atrygfhDmOANDIWDxxNQgOjF0= 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=G8RNO31V; 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="G8RNO31V" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=7g6iAwZiTiUnLNkvhRAcJnQ/fu6sja7lcOWC+zaEIkg=; b=G8RNO31Vlh/2uRuxwk+HZhw2q+ UkgVnd263L7FBVZf/fCtCThg6/oSYDZGDvekUf5IZ+ZorvAbHNZRx+KHK0c/5OAaV70i70r+dt3wD gZFkvKz7BifOohkj5mZWkGBG+NVDmXJQoU/j08Qyw7jWLkqnehuMkMMUZ9MHKX9jQ0SQ4qAQ7NO4S sMrG4h69IuYOdWXM7QQJzmSCsPAehUqPDOcAfKR7gvCUHEEPczMYz1a/HCQlmBN/crNVNQQ1nOqd3 n++OongKwZd/J1ETggAcJctQ14Tw4Ti5ww1OD+UOgDXJa0r8YmOHrl+o/7pfzONdl3BO4H3kthN4/ IcLilQIA==; Received: from hch by bombadil.infradead.org with local (Exim 4.98.2 #2 (Red Hat Linux)) id 1uh7ZS-00000001i0N-1T3s; Wed, 30 Jul 2025 14:14:18 +0000 Date: Wed, 30 Jul 2025 07:14:18 -0700 From: Christoph Hellwig To: Tony Battersby Cc: Song Liu , Yu Kuai , Christian Brauner , "Darrick J. Wong" , "Matthew Wilcox (Oracle)" , linux-raid@vger.kernel.org, linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/2] iomap: align writeback to RAID stripe boundaries Message-ID: References: <55deda1d-967d-4d68-a9ba-4d5139374a37@cybernetics.com> Precedence: bulk X-Mailing-List: linux-fsdevel@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: <55deda1d-967d-4d68-a9ba-4d5139374a37@cybernetics.com> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html On Tue, Jul 29, 2025 at 12:13:42PM -0400, Tony Battersby wrote: > Improve writeback performance to RAID-4/5/6 by aligning writes to stripe > boundaries. This relies on io_opt being set to the stripe size (or > a multiple) when BLK_FEAT_RAID_PARTIAL_STRIPES_EXPENSIVE is set. You're not aligning anything. You are splitting I/O, which is exactly what we've been trying to avoid by moving to the immutable bio_vec model that moves the splitting to the place that needs it. > Benchmark of sequential writing to a large file on XFS using > io_uring with 8-disk md-raid6: > Before: 601.0 MB/s > After: 614.5 MB/s > Improvement: +2.3% Looks like you need to do some work on the bio splitting in RAID. It would help to Cc the maintainers as the driver is actually pretty actively worked on these days.