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 X-Spam-Level: X-Spam-Status: No, score=-10.1 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DA308C4363D for ; Fri, 25 Sep 2020 11:36:14 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 58B082075E for ; Fri, 25 Sep 2020 11:36:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="XlD4lbvf" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 58B082075E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:39998 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kLm1M-0005pe-BK for qemu-devel@archiver.kernel.org; Fri, 25 Sep 2020 07:36:12 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:59516) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kLm0f-000505-UH for qemu-devel@nongnu.org; Fri, 25 Sep 2020 07:35:29 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:36070) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1kLm0e-0000Et-2o for qemu-devel@nongnu.org; Fri, 25 Sep 2020 07:35:29 -0400 Dkim-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1601033727; 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=8wbKWqSEdwRPS+cJHs9ki71kWr+XRUJYMEk4oqcfksU=; b=XlD4lbvfbXLDDmDreNowoWxIFzodZTEb7W0FS2KYSZ8freJUk4cqU56VnFUdI/n2BYl45v 8C4dXimoiTTe8zRY0tdHBe7/A9hECkMWcL5Qf2pretCletth7a5/Z7L2SCbPH19kuHnzly W+IHzj7vEPUcE5+LAxU0ThB9ORejNz8= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-237-gfPK_doGP_2s_yA2HJ5mxg-1; Fri, 25 Sep 2020 07:35:24 -0400 X-MC-Unique: gfPK_doGP_2s_yA2HJ5mxg-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 738CF871805; Fri, 25 Sep 2020 11:35:23 +0000 (UTC) Received: from work-vm (ovpn-114-177.ams2.redhat.com [10.36.114.177]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 21FD91002C1B; Fri, 25 Sep 2020 11:35:14 +0000 (UTC) Date: Fri, 25 Sep 2020 12:35:12 +0100 From: "Dr. David Alan Gilbert" To: Chirantan Ekbote Subject: Re: [Virtio-fs] tools/virtiofs: Multi threading seems to hurt performance Message-ID: <20200925113512.GH2873@work-vm> References: <20200918213436.GA3520@redhat.com> MIME-Version: 1.0 In-Reply-To: User-Agent: Mutt/1.14.6 (2020-07-11) X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=dgilbert@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Received-SPF: pass client-ip=216.205.24.124; envelope-from=dgilbert@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/09/25 02:48:20 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -32 X-Spam_score: -3.3 X-Spam_bar: --- X-Spam_report: (-3.3 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1.199, 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_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=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: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: virtio-fs-list , qemu-devel@nongnu.org, Vivek Goyal Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" * Chirantan Ekbote (chirantan@chromium.org) wrote: > On Sat, Sep 19, 2020 at 6:36 AM Vivek Goyal wrote: > > > > Hi All, > > > > virtiofsd default thread pool size is 64. To me it feels that in most of > > the cases thread pool size 1 performs better than thread pool size 64. > > > > I ran virtiofs-tests. > > > > https://github.com/rhvgoyal/virtiofs-tests > > > > And here are the comparision results. To me it seems that by default > > we should switch to 1 thread (Till we can figure out how to make > > multi thread performance better even when single process is doing > > I/O in client). > > > > FWIW, we've observed the same behavior in crosvm. Using a thread pool > for the virtiofs server consistently gave us worse performance than > using a single thread. Interesting; so it's not just us doing something silly! It does feel like you *should* be able to get some benefit from multiple threads; so I guess some more investigation needed at some time. Dave > Chirantan > > _______________________________________________ > Virtio-fs mailing list > Virtio-fs@redhat.com > https://www.redhat.com/mailman/listinfo/virtio-fs -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK