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 D7B6BD29C56 for ; Mon, 19 Jan 2026 18:17:42 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1vhto4-0000n2-2M; Mon, 19 Jan 2026 13:16:55 -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 1vhtnu-0000jG-Pv for qemu-devel@nongnu.org; Mon, 19 Jan 2026 13:16:44 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1vhtnt-0006BW-4B for qemu-devel@nongnu.org; Mon, 19 Jan 2026 13:16:42 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1768846598; 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=8PpcMtrNpaK+JdxA1c+gRL5Jz2pcpGS1AKnpotrEolY=; b=Fi5OqCak52xbZiofcfh5BSCeqKnT0ns5kFZVOJdBmoUPgF747UrFUbcL0HGbjC6TKD3/yh hTVT2q5QiaPK30xl3hz0JFDf/nJ5epRdRR0hy5xY79gcrLp1mwUHfXmUqMlmzoZOZitlTv RNbF8W1UZQxTw2fVe9jEQN3nNmpD+P0= 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-635-P2DfIHM6M9-5SK-jr-7cdw-1; Mon, 19 Jan 2026 13:16:35 -0500 X-MC-Unique: P2DfIHM6M9-5SK-jr-7cdw-1 X-Mimecast-MFC-AGG-ID: P2DfIHM6M9-5SK-jr-7cdw_1768846594 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 EC24119560A1; Mon, 19 Jan 2026 18:16:32 +0000 (UTC) Received: from localhost (unknown [10.2.16.150]) by mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id AE5DC19560AB; Mon, 19 Jan 2026 18:16:31 +0000 (UTC) Date: Mon, 19 Jan 2026 13:16:30 -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: <20260119181630.GA834718@fedora> References: <20260113174824.464720-1-jhkim@linux.ibm.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="e9hiSGwfhh+z78tS" Content-Disposition: inline In-Reply-To: <20260113174824.464720-1-jhkim@linux.ibm.com> X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 Received-SPF: pass client-ip=170.10.129.124; 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=-0.016, 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_H2=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_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 --e9hiSGwfhh+z78tS Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable 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-disk > 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 varying > 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 (sequential > 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? 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