From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) (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 B29D823371E for ; Mon, 2 Jun 2025 14:19:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=213.95.11.211 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748873953; cv=none; b=Gfi5ZJ5qIzB75awc4lNBYcHfBnh52mZpFLwH0wr18FlOe0OM3OMzRUUjc7y8zIYJxy4aKm5Jy66tkD+4Rpx+C+gZBBR8EsyQqXif1OQMz81a/SAkwVTbkRtD8673tP/DOmg7F8EZTQQngDjbKB8K6tQBX7h5LmXib5pNSoxY918= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748873953; c=relaxed/simple; bh=4E11vaf+KaP/92AGKGJWyssk3PUKD8Kp2pFck3kO4yI=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=mJl4SmETbQK5pHteRh7fZJqpKH/J2y0pksyN5sKkXusWr2Wcf/HdMFBvLohIjTCDdPbtgOOk+bamFChNRZLQzfwM3a/O+keTksA6pJDB8ySM10pXBFFOthcjZZ0VaCtME5849b8u6TZs2CDmh5mTJywldAgMmMYtZVI4v6Tn4d4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=lst.de; spf=pass smtp.mailfrom=lst.de; arc=none smtp.client-ip=213.95.11.211 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=lst.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=lst.de Received: by verein.lst.de (Postfix, from userid 2407) id D587968C7B; Mon, 2 Jun 2025 16:19:04 +0200 (CEST) Date: Mon, 2 Jun 2025 16:19:04 +0200 From: Christoph Hellwig To: Kundan Kumar Cc: jaegeuk@kernel.org, chao@kernel.org, viro@zeniv.linux.org.uk, brauner@kernel.org, jack@suse.cz, miklos@szeredi.hu, agruenba@redhat.com, trondmy@kernel.org, anna@kernel.org, akpm@linux-foundation.org, willy@infradead.org, mcgrof@kernel.org, clm@meta.com, david@fromorbit.com, amir73il@gmail.com, axboe@kernel.dk, hch@lst.de, ritesh.list@gmail.com, djwong@kernel.org, dave@stgolabs.net, p.raghav@samsung.com, da.gomez@samsung.com, linux-f2fs-devel@lists.sourceforge.net, linux-fsdevel@vger.kernel.org, gfs2@lists.linux.dev, linux-nfs@vger.kernel.org, linux-mm@kvack.org, gost.dev@samsung.com Subject: Re: [PATCH 00/13] Parallelizing filesystem writeback Message-ID: <20250602141904.GA21996@lst.de> References: <20250529111504.89912-1-kundan.kumar@samsung.com> Precedence: bulk X-Mailing-List: gfs2@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250529111504.89912-1-kundan.kumar@samsung.com> User-Agent: Mutt/1.5.17 (2007-11-01) On Thu, May 29, 2025 at 04:44:51PM +0530, Kundan Kumar wrote: > Number of writeback contexts > =========================== > The plan is to keep the nr_wb_ctx as 1, ensuring default single threaded > behavior. However, we set the number of writeback contexts equal to > number of CPUs in the current version. Later we will make it configurable > using a mount option, allowing filesystems to choose the optimal number > of writeback contexts. Well, the proper thing would be to figure out a good default and not just keep things as-is, no? > IOPS and throughput > =================== > We see significant improvement in IOPS across several filesystem on both > PMEM and NVMe devices. > > Performance gains: > - On PMEM: > Base XFS : 544 MiB/s > Parallel Writeback XFS : 1015 MiB/s (+86%) > Base EXT4 : 536 MiB/s > Parallel Writeback EXT4 : 1047 MiB/s (+95%) > > - On NVMe: > Base XFS : 651 MiB/s > Parallel Writeback XFS : 808 MiB/s (+24%) > Base EXT4 : 494 MiB/s > Parallel Writeback EXT4 : 797 MiB/s (+61%) What worksload was this? How many CPU cores did the system have, how many AGs/BGs did the file systems have? What SSD/Pmem was this? Did this change the write amp as measure by the media writes on the NVMe SSD? Also I'd be really curious to see numbers on hard drives. > We also see that there is no increase in filesystem fragmentation > # of extents: > - On XFS (on PMEM): > Base XFS : 1964 > Parallel Writeback XFS : 1384 > > - On EXT4 (on PMEM): > Base EXT4 : 21 > Parallel Writeback EXT4 : 11 How were the number of extents counts given that they look so wildly different? From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.sourceforge.net (lists.sourceforge.net [216.105.38.7]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id B1618C54FB3 for ; Mon, 2 Jun 2025 14:19:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.sourceforge.net; s=beta; h=Content-Transfer-Encoding:Content-Type:Cc: List-Subscribe:List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id: Subject:In-Reply-To:MIME-Version:References:Message-ID:To:From:Date:Sender: Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender :Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=PS+1KbJ3J9jUCuX+BJlqGQU9U7IUtwm4uwpS1Dh0BNg=; b=FSE/hZMMck7G3VHuVm8KbW3yWu DwTl4ZKmZvQJC/zKF8FzFbcCujLiX7kL+HmGZcDRDoYBYHAPTY2nz0XjtFGFx9c08z105WwYGek4O HDDsJMbR5919cMn2ayZqUi9exPua4+EduqB+bX5SvTkXkVQGsXqwerxQC7CsIzsc5U8o=; Received: from [127.0.0.1] (helo=sfs-ml-1.v29.lw.sourceforge.com) by sfs-ml-1.v29.lw.sourceforge.com with esmtp (Exim 4.95) (envelope-from ) id 1uM60Y-00069d-HY; Mon, 02 Jun 2025 14:19:22 +0000 Received: from [172.30.29.66] (helo=mx.sourceforge.net) by sfs-ml-1.v29.lw.sourceforge.com with esmtps (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.95) (envelope-from ) id 1uM60W-00069V-Ns for linux-f2fs-devel@lists.sourceforge.net; Mon, 02 Jun 2025 14:19:20 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sourceforge.net; s=x; 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:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=32enGM4pZj92pLRTC2laWAPPMMGLKlbi51pBb1slNZ0=; b=MvwuI5I6zasV/xDTopzhD+loaV 8hOgiuJS0RR2/7kd+uTIv5r6VuctiEPa6+jvIeDe+KChfY9zggYkMQ+t0BQciZG4QETxZRctKA9Tq NG66yIyKWecyDioxRJLNHjD4MKQHwGtOAAZPuOJw1/QR7LZOkuSnci4J3JRj7wZzE3jQ=; DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sf.net; s=x ; 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:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=32enGM4pZj92pLRTC2laWAPPMMGLKlbi51pBb1slNZ0=; b=X6cvdGnQ6MWPgmGCcWq4R5wWJN UC9wJbfYgdnbYZsz1rBMr8GiMzWnawUj9p98X/mT49FhTXI1n2CmeYA11mU1Zw93jzhNlikp2mr+g +8RRzvTe9OkEYmezoEITG33AwpYwxV8KWBimDl7jHogjT855/D3XCckfa0FUV9FYzYkI=; Received: from verein.lst.de ([213.95.11.211]) by sfi-mx-2.v28.lw.sourceforge.com with esmtps (TLS1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.95) id 1uM60V-0002CA-Mt for linux-f2fs-devel@lists.sourceforge.net; Mon, 02 Jun 2025 14:19:20 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id D587968C7B; Mon, 2 Jun 2025 16:19:04 +0200 (CEST) Date: Mon, 2 Jun 2025 16:19:04 +0200 From: Christoph Hellwig To: Kundan Kumar Message-ID: <20250602141904.GA21996@lst.de> References: <20250529111504.89912-1-kundan.kumar@samsung.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20250529111504.89912-1-kundan.kumar@samsung.com> User-Agent: Mutt/1.5.17 (2007-11-01) X-Headers-End: 1uM60V-0002CA-Mt Subject: Re: [f2fs-dev] [PATCH 00/13] Parallelizing filesystem writeback X-BeenThere: linux-f2fs-devel@lists.sourceforge.net X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: ritesh.list@gmail.com, jack@suse.cz, djwong@kernel.org, amir73il@gmail.com, david@fromorbit.com, gfs2@lists.linux.dev, linux-mm@kvack.org, clm@meta.com, hch@lst.de, dave@stgolabs.net, agruenba@redhat.com, miklos@szeredi.hu, gost.dev@samsung.com, willy@infradead.org, p.raghav@samsung.com, linux-nfs@vger.kernel.org, da.gomez@samsung.com, viro@zeniv.linux.org.uk, jaegeuk@kernel.org, axboe@kernel.dk, brauner@kernel.org, linux-f2fs-devel@lists.sourceforge.net, mcgrof@kernel.org, anna@kernel.org, linux-fsdevel@vger.kernel.org, akpm@linux-foundation.org, trondmy@kernel.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-f2fs-devel-bounces@lists.sourceforge.net On Thu, May 29, 2025 at 04:44:51PM +0530, Kundan Kumar wrote: > Number of writeback contexts > =========================== > The plan is to keep the nr_wb_ctx as 1, ensuring default single threaded > behavior. However, we set the number of writeback contexts equal to > number of CPUs in the current version. Later we will make it configurable > using a mount option, allowing filesystems to choose the optimal number > of writeback contexts. Well, the proper thing would be to figure out a good default and not just keep things as-is, no? > IOPS and throughput > =================== > We see significant improvement in IOPS across several filesystem on both > PMEM and NVMe devices. > > Performance gains: > - On PMEM: > Base XFS : 544 MiB/s > Parallel Writeback XFS : 1015 MiB/s (+86%) > Base EXT4 : 536 MiB/s > Parallel Writeback EXT4 : 1047 MiB/s (+95%) > > - On NVMe: > Base XFS : 651 MiB/s > Parallel Writeback XFS : 808 MiB/s (+24%) > Base EXT4 : 494 MiB/s > Parallel Writeback EXT4 : 797 MiB/s (+61%) What worksload was this? How many CPU cores did the system have, how many AGs/BGs did the file systems have? What SSD/Pmem was this? Did this change the write amp as measure by the media writes on the NVMe SSD? Also I'd be really curious to see numbers on hard drives. > We also see that there is no increase in filesystem fragmentation > # of extents: > - On XFS (on PMEM): > Base XFS : 1964 > Parallel Writeback XFS : 1384 > > - On EXT4 (on PMEM): > Base EXT4 : 21 > Parallel Writeback EXT4 : 11 How were the number of extents counts given that they look so wildly different? _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel