From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="UkPzaIjQ" Received: from mgamail.intel.com (mgamail.intel.com [134.134.136.24]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B63D6F5 for ; Mon, 27 Nov 2023 04:21:50 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1701087710; x=1732623710; h=date:from:to:cc:subject:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=N6O7KSlgZkTTDgZPIEVbV5nH9TojttJ95dfdKCb25vk=; b=UkPzaIjQ01jb5RAuAcSkFeXOcLgY1NgxqrxOkoaxyzV1uBL89jXZefCI guBKfrzbu6n2ulkwBSs+CyJAXkTSzMiFbfuK8Imcy1Hj9o/xM5gap/tGw JEIZmGufcbisT032yi6K1c+ixQVK8Ej221bMDZuAZ3Mnav6O0inn9pzFw CgiR0LzoVYHOGV40kaAb8bnHxac31nTL68A9KzDuwSKzaPcuEYnsJnfoA wpSKH2OBQS8fKCTCn9hOoW4IhCpkt5pMIAPyNDbCy8BC7QR494UVUo3Nu b+SZgCADC/FnsIFAOGZ8SzV/Vqe2XgmiLxSTjOrcSSKf2JfV7D1iI9Z/j g==; X-IronPort-AV: E=McAfee;i="6600,9927,10906"; a="395507510" X-IronPort-AV: E=Sophos;i="6.04,230,1695711600"; d="scan'208";a="395507510" Received: from orsmga005.jf.intel.com ([10.7.209.41]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Nov 2023 04:21:50 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10906"; a="941542642" X-IronPort-AV: E=Sophos;i="6.04,230,1695711600"; d="scan'208";a="941542642" Received: from cdewhirx-mobl.amr.corp.intel.com (HELO peluse-desk5) ([10.209.163.221]) by orsmga005-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Nov 2023 04:21:49 -0800 Date: Mon, 27 Nov 2023 04:21:48 -0800 From: Paul E Luse To: Christoph Hellwig Cc: Yiming Xu , song@kernel.org, linux-raid@vger.kernel.org, paul.e.luse@intel.com, firnyee@gmail.com Subject: Re: [RFC] md/raid5: optimize RAID5 performance. Message-ID: <20231127042148.3b9bee3f@peluse-desk5> In-Reply-To: References: X-Mailer: Claws Mail 4.1.1 (GTK 3.24.38; aarch64-redhat-linux-gnu) Precedence: bulk X-Mailing-List: linux-raid@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Sun, 26 Nov 2023 22:44:45 -0800 Christoph Hellwig wrote: > Hi Shushu, > > the work certainly looks interesting! > > However: > > > Optimized by using fine-grained locks, customized data structures, > > and scattered address space. Achieves significant improvements in > > both throughput and latency. > > this is a lot of work for a single Linux patch, we usually do that > work pice by pice instead of complete rewrite, and for such > signigicant changes the commit logs also tend to be a bit extensive. > > I'm also not quite sure what scattered address spaces are - I bet > reading the paper (I plan to get to that) would explain it, but it > also helps to explain the idea in the commit message. > > That's my high level nitpicking for now, I'll try to read the paper > and the patch in detail and come back later. > > For sure the paper provides a lot more context. Is there more performance data avialble, like a general sweep of various IO sizes, patterns and queue depths? ALso, what kind of data integrity testing has been done?