From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 D7295199E8D for ; Wed, 11 Jun 2025 15:10:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749654655; cv=none; b=OAMhhBAo1CnoPld8or9xMJd3LO3VUT8HEbqDX9LQtLrt7unLukbVm3aHQDERW/EE9VjVlNuccpzGofim18wCzISTQiN74EDLCZHMLKlkcKHOKOdxanxomeDgyvaZndA/eyJ+z9CdgxE4tc82lT+5mh9ra0JILPMVPme+XXCaFvo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749654655; c=relaxed/simple; bh=J+Cb82L7O/BiPrcKvhRJcV6B/aNRdSmFiESgx/lMDDQ=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=p/bUvX1QWXE2s8JFwleB0yNd8yG4gHnjIcY7EOiymVd/vl8l1qCUcK6OCgj3X775EyU8tgeiRRKcn5m5ZdD4KJPdN/IMlszPdJUfJ5pyXZOtpXo1p6/MSr6O9Fq458opGIShNI+MyImNhjaRQrirSfISd4xHAa7OXYKFQAqGVuM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=gUxILMLX; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="gUxILMLX" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1749654652; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=lWkNewhRJ4wpEDm7PPC52E6cJKu2Um4iV+x8uvVQe/M=; b=gUxILMLX+kN8XKOfs4UCUAC/gsPzyJVIhtFoqKhztfp9bTaWpvBcHsy6ZP6WdicN9KEWxG M5q3683wbhES4NuiqWqRT8m6ktmplucYBDA5Ee65Rk/y/Dppzd9JBX4VXzZQXzlYtsT4Za zpaOtYJ4DTdsg8S1Y5OHcHSIsLr0Uc0= Received: from mx-prod-mc-02.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-94-zveqg8ABN8KQBI07Ze_SoA-1; Wed, 11 Jun 2025 11:10:49 -0400 X-MC-Unique: zveqg8ABN8KQBI07Ze_SoA-1 X-Mimecast-MFC-AGG-ID: zveqg8ABN8KQBI07Ze_SoA_1749654647 Received: from mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.15]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-02.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 69F09195604F; Wed, 11 Jun 2025 15:10:46 +0000 (UTC) Received: from fedora (unknown [10.72.116.18]) by mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 4AFD11956087; Wed, 11 Jun 2025 15:10:33 +0000 (UTC) Date: Wed, 11 Jun 2025 23:10:28 +0800 From: Ming Lei To: Hazem Mohamed Abuelfotoh Cc: stable@vger.kernel.org, kernel test robot , Hagar Hemdan , Shaoying Xu , Jens Axboe , "Michael S. Tsirkin" , Jason Wang , Paolo Bonzini , Stefan Hajnoczi , Eugenio =?iso-8859-1?Q?P=E9rez?= , Xuan Zhuo , Keith Busch , Christoph Hellwig , Sagi Grimberg , linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, virtualization@lists.linux.dev, linux-nvme@lists.infradead.org, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH] Revert "block: don't reorder requests in blk_add_rq_to_plug" Message-ID: References: <20250611121626.7252-1-abuehaze@amazon.com> Precedence: bulk X-Mailing-List: virtualization@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: <20250611121626.7252-1-abuehaze@amazon.com> X-Scanned-By: MIMEDefang 3.0 on 10.30.177.15 On Wed, Jun 11, 2025 at 12:14:54PM +0000, Hazem Mohamed Abuelfotoh wrote: > This reverts commit e70c301faece15b618e54b613b1fd6ece3dd05b4. > > Commit ("block: don't reorder requests in > blk_add_rq_to_plug") reversed how requests are stored in the blk_plug > list, this had significant impact on bio merging with requests exist on > the plug list. This impact has been reported in [1] and could easily be > reproducible using 4k randwrite fio benchmark on an NVME based SSD without > having any filesystem on the disk. > > My benchmark is: > > fio --time_based --name=benchmark --size=50G --rw=randwrite \ > --runtime=60 --filename="/dev/nvme1n1" --ioengine=psync \ > --randrepeat=0 --iodepth=1 --fsync=64 --invalidate=1 \ > --verify=0 --verify_fatal=0 --blocksize=4k --numjobs=4 \ > --group_reporting > > On 1.9TiB SSD(180K Max IOPS) attached to i3.16xlarge AWS EC2 instance. > > Kernel | fio (B.W MiB/sec) | I/O size (iostat) > --------------+---------------------+-------------------- > 6.15.1 | 362 | 2KiB > 6.15.1+revert | 660 (+82%) | 4KiB > --------------+---------------------+-------------------- I just run one quick test in my test VM, but can't reproduce it. Also be curious, why does writeback produce so many 2KiB bios? Thanks, Ming