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.gnu.org (lists.gnu.org [209.51.188.17]) (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 90080D2FEDF for ; Tue, 27 Jan 2026 21:12:07 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1vkqLd-00062c-Dn; Tue, 27 Jan 2026 16:11:41 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1vkqLb-0005y5-11 for qemu-devel@nongnu.org; Tue, 27 Jan 2026 16:11:39 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1vkqLZ-0000jW-7p for qemu-devel@nongnu.org; Tue, 27 Jan 2026 16:11:38 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1769548295; 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=151sA2ra38p1Qj6qwzYiO0e1Neofg2v6sxBOTrXd73M=; b=Dp9RK7GApjQGIq5PcnjPUO2nh2ACn2Gq91fsdbkFPSeMsqoUzLAm2puSY1u9Ds89ticjo7 Cg+7By+JlcBu81PKO1amI2x+F9rMhXFBleS4l5cShQ5LBhjwYuHv+7Wscmbu9ByKMDL3kK 1nx1muvHVuoWIoXHQwd7ixZMu/p/Pl4= Received: from mx-prod-mc-05.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-640-bWNWaEw9N8GY1itPYbGsug-1; Tue, 27 Jan 2026 16:11:26 -0500 X-MC-Unique: bWNWaEw9N8GY1itPYbGsug-1 X-Mimecast-MFC-AGG-ID: bWNWaEw9N8GY1itPYbGsug_1769548284 Received: from mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.17]) (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-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id DEF68195608D; Tue, 27 Jan 2026 21:11:23 +0000 (UTC) Received: from localhost (unknown [10.2.16.97]) by mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 6EB9F1956095; Tue, 27 Jan 2026 21:11:22 +0000 (UTC) Date: Tue, 27 Jan 2026 16:11:21 -0500 From: Stefan Hajnoczi To: JAEHOON KIM Cc: qemu-devel@nongnu.org, qemu-block@nongnu.org, pbonzini@redhat.com, fam@euphon.net, armbru@redhat.com, eblake@redhat.com, berrange@redhat.com, eduardo@habkost.net, dave@treblig.org, sw@weilnetz.de Subject: Re: [PATCH RFC v1 0/3] aio-poll: improve aio-polling efficiency Message-ID: <20260127211121.GB96301@fedora> References: <20260113174824.464720-1-jhkim@linux.ibm.com> <20260119181630.GA834718@fedora> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="uJYxvatJWw5rzBre" Content-Disposition: inline In-Reply-To: X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 Received-SPF: pass client-ip=170.10.133.124; envelope-from=stefanha@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: qemu development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org --uJYxvatJWw5rzBre Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, Jan 23, 2026 at 01:15:04PM -0600, JAEHOON KIM wrote: > On 1/19/2026 12:16 PM, Stefan Hajnoczi wrote: > > On Tue, Jan 13, 2026 at 11:48:21AM -0600, Jaehoon Kim wrote: > > > We evaluated the patches on an s390x host with a single guest using 16 > > > virtio block devices backed by FCP multipath devices in a separate-di= sk > > > setup, with the I/O scheduler set to 'none' in both host and guest. > > >=20 > > > The fio workload included sequential and random read/write with varyi= ng > > > numbers of jobs (1,4,8,16) and io_depth of 8. The tests were conducted > > > with single and dual iothreads, using the newly introduced poll-weight > > > parameter to measure their impact on CPU cost and throughput. > > >=20 > > > Compared to the baseline, across four FIO workload patterns (sequenti= al > > > R/W, random R/W), and averaged over FIO job counts of 1, 4, 8, and 16, > > > throughput decreased slightly (-3% to -8% for one iothread, -2% to -5% > > > for two iothreads), while CPU usage on the s390x host dropped > > > significantly (-10% to -25% and -7% to -12%, respectively). > > Hi Jaehoon, > > I would like to run the same fio benchmarks on a local NVMe drive (<10us > > request latency) to see how that type of hardware configuration is > > affected. Are the scripts and fio job files available somewhere? > >=20 > > Thanks, > > Stefan >=20 > Thank you for your reply. > The fio scripts are not available in a location you can access, but there= is nothing particularly special in the settings. > I=E2=80=99m sharing below the methodology and test setup used by our perf= ormance team. >=20 > Guest Setup > ---------------------- > - 12 vCPUs, 4 GiB memory > - 16 virtio disks based on the FCP multipath devices in the host >=20 > FIO test parameters > ----------------------- > - FIO Version: fio-3.33 > - Filesize: 2G > - Blocksize: 8K / 128K > - Direct I/O: 1 > - FIO I/O Engine: libaio > - NUMJOB List: 1, 4, 8, 16 > - IODEPTH: 8 > - Runtime (s): 150 >=20 > Two FIO samples for random read > -------------------------------- > fio --direct=3D1 --name=3Dtest --numjobs=3D16 --filename=3Dbase.0.0:base.= 1.0:base.2.0:base.3.0:base.4.0:base.5.0:base.6.0:base.7.0:base.8.0:base.9.0= :base.10.0:base.11.0:base.12.0:base.13.0:base.14.0:base.15.0 --size=3D32G = --time_based --runtime=3D4m --readwrite=3Drandread --ioengine=3Dlibaio --io= depth=3D8 --bs=3D8k > fio --direct=3D1 --name=3Dtest --numjobs=3D4 --filename=3Dsubw1/base.0.0= :subw4/base.3.0:subw8/base.7.0:subw12/base.11.0:subw16/base.15.0 = --size=3D8G = --time_based --runtime=3D4m --readwrite=3Drandread --ioengine=3Dlibaio --io= depth=3D8 --bs=3D8k >=20 >=20 > additional notes > ---------------- > - Each file is placed on a separate disk device mounted under subw as = specified in --filename=3D.... > - We execute one warmup run, then two measurement runs and calculate the = average Thanks, I will share x86_64 with fast local NVMe results when I have collec= ted them. Stefan --uJYxvatJWw5rzBre Content-Type: application/pgp-signature; name=signature.asc -----BEGIN PGP SIGNATURE----- iQEzBAEBCgAdFiEEhpWov9P5fNqsNXdanKSrs4Grc8gFAml5KfkACgkQnKSrs4Gr c8jwQAf9GTc2nMoP4dxH/rl7siY1kYFurW4V/vbMFXBxCkFATI0p4Nls5PjEVPBJ cnC8Xf8lUNaCd0P9Cfq/l3pbWXFPjPyQuZgvmD0soleFzka1vYxILICFV/wCnleD mEvxw4bve5Lha62qUCmEhMjdI433L6atLdcwUZM2PHACagUjnhFmCuytdPQo7NWj UPQ9SscPaWdBv5vOwhewchSL85NzlJcuNSwSlpnt+Ux/gfeScznUZTHKhE0jqO+L YHk6y5ZT8OHUUS87ENSObuLpmU+wUiQ/xF/jKM+k/BmEOqXDL8Gcpf42/q2Akg3F W16rvxDUVflzjVo8DL0yv61egb/5dg== =I18m -----END PGP SIGNATURE----- --uJYxvatJWw5rzBre--