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=-15.1 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,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 C2194C433E0 for ; Tue, 16 Feb 2021 17:57:21 +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 168FF64DAF for ; Tue, 16 Feb 2021 17:57:20 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 168FF64DAF 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]:50370 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lC4b9-0005nj-TK for qemu-devel@archiver.kernel.org; Tue, 16 Feb 2021 12:57:19 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:52926) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lC4ZW-0004uf-EG for qemu-devel@nongnu.org; Tue, 16 Feb 2021 12:55:38 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:32484) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1lC4ZU-0003a2-Ua for qemu-devel@nongnu.org; Tue, 16 Feb 2021 12:55:38 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1613498136; 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=jYG1pogPeorXiNbGkjpg4X6ddLmVfeeGhcxb8D4tEcY=; b=P87/FYNw3iuQYC5gmE0ct8Y2OHuOZpAMFkZ7bK7ZcM8NE2M31YwrxQvy94CpTdgaLEdBw4 E6nQcSrdOunlLXAzXmU48qVbd9qMUbNhIlLE84g8yTdZX8wF7Vam4trkYk77hWGVAvZTWf T276Bz5WVqq+kOn7k3+9vcYRkCoaKd4= 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-472-hYmhFWk8P4mz0GiWVQLHRA-1; Tue, 16 Feb 2021 12:55:34 -0500 X-MC-Unique: hYmhFWk8P4mz0GiWVQLHRA-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 523368799F1 for ; Tue, 16 Feb 2021 17:55:33 +0000 (UTC) Received: from work-vm (ovpn-115-109.ams2.redhat.com [10.36.115.109]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 7726360C15; Tue, 16 Feb 2021 17:55:29 +0000 (UTC) Date: Tue, 16 Feb 2021 17:55:26 +0000 From: "Dr. David Alan Gilbert" To: Vivek Goyal Subject: Re: [Virtio-fs] [PATCH 1/1] virtiofsd: Do not use a thread pool by default Message-ID: References: <20210210182744.27324-1-vgoyal@redhat.com> <20210210182744.27324-2-vgoyal@redhat.com> MIME-Version: 1.0 In-Reply-To: <20210210182744.27324-2-vgoyal@redhat.com> User-Agent: Mutt/2.0.5 (2021-01-21) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 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=63.128.21.124; envelope-from=dgilbert@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 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_LOW=-0.7, RCVD_IN_MSPIKE_H4=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@redhat.com, qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" * Vivek Goyal (vgoyal@redhat.com) wrote: > Currently we created a thread pool (With 64 max threads per pool) for > each virtqueue. We hoped that this will provide us with better scalability > and performance. > > But in practice, we are getting better numbers in most of the cases > when we don't create a thread pool at all and a single thread per > virtqueue receives the request and processes it. > > Hence, I am proposing that we switch to no thread pool by default > (equivalent of --thread-pool-size=0). This will provide out of > box better performance to most of the users. In fact other users > have confirmed that not using a thread pool gives them better > numbers. So why not use this as default. It can be changed when > somebody can fix the issues with thread pool performance. > > Signed-off-by: Vivek Goyal OK, lets try it - I still worry it really means we're missing something silly about them, you'd really think eventually the threads should help. Reviewed-by: Dr. David Alan Gilbert > --- > tools/virtiofsd/fuse_lowlevel.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/tools/virtiofsd/fuse_lowlevel.c b/tools/virtiofsd/fuse_lowlevel.c > index e94b71110b..fbdf62ee9b 100644 > --- a/tools/virtiofsd/fuse_lowlevel.c > +++ b/tools/virtiofsd/fuse_lowlevel.c > @@ -18,7 +18,7 @@ > > #include > > -#define THREAD_POOL_SIZE 64 > +#define THREAD_POOL_SIZE 0 > > #define OFFSET_MAX 0x7fffffffffffffffLL > > -- > 2.25.4 -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK