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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 66BC4C7618B for ; Thu, 25 Jul 2019 14:42:38 +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 369CE2173B for ; Thu, 25 Jul 2019 14:42:38 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 369CE2173B 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]:60746 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hqex3-00027S-6N for qemu-devel@archiver.kernel.org; Thu, 25 Jul 2019 10:42:37 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:37882) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hqews-0001im-3R for qemu-devel@nongnu.org; Thu, 25 Jul 2019 10:42:26 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hqewr-00061Y-7s for qemu-devel@nongnu.org; Thu, 25 Jul 2019 10:42:26 -0400 Received: from mail-qt1-f194.google.com ([209.85.160.194]:43507) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1hqewr-00061D-45 for qemu-devel@nongnu.org; Thu, 25 Jul 2019 10:42:25 -0400 Received: by mail-qt1-f194.google.com with SMTP id w17so4977069qto.10 for ; Thu, 25 Jul 2019 07:42:24 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=tWj9lHT2quf4xVRDpOVqU4hyVOauLdD76qXV3ZKsQUk=; b=k/0KvOhGFkTOvYKetNI/jPxxD1FY1Uh9y8bjwymGhbNKt0Ir+HsF6PWlqLESF8QXqI WgjNFRIhUDUyhVo9Ne0eh1RVT1Ch13LFObpdqEEjnjEXl/hFSl9IZPe3QgFYIPPNUdX/ p0XeQkRil9uYbdsnCcjKUrw3eNvn+l7WWl0Y2kLvUU+K+HxJ0Ag4Ls0ov//1uVBid4ic 0mkZHoqr7i4PxFnGWT3KTuCOLKBTS58MgugCuyDw8jx4ufkt2rOaXEodEiJuIvOEit3O aNjUJyAf8xaqz2WolTg3RcOyaUooKs7N8SF/v8jM+RMi/yWKCj5uUsrKjQcy+PW7Hc3i t09A== X-Gm-Message-State: APjAAAWhdcW6yYh/IZqMUUVEBhXvme/wFA6vwa8MJBqi8GE6k4fgKno1 REVbkBgnYrmeM749tfn1YdFemw== X-Google-Smtp-Source: APXvYqz++3ITpRGeNySS4XB6ESOhAgLBvKtUVx4DY4TzVN4wxwpFhlvvTTxJjn5YB6CjIHDtdk8ZvQ== X-Received: by 2002:a0c:ad07:: with SMTP id u7mr61834415qvc.2.1564065744584; Thu, 25 Jul 2019 07:42:24 -0700 (PDT) Received: from redhat.com (bzq-79-181-91-42.red.bezeqint.net. [79.181.91.42]) by smtp.gmail.com with ESMTPSA id f26sm28329866qtf.44.2019.07.25.07.42.20 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Thu, 25 Jul 2019 07:42:23 -0700 (PDT) Date: Thu, 25 Jul 2019 10:42:17 -0400 From: "Michael S. Tsirkin" To: Paolo Bonzini Message-ID: <20190725103636-mutt-send-email-mst@kernel.org> References: <20190725055908-mutt-send-email-mst@kernel.org> <87pnlymm47.fsf@redhat.com> <20190725080556-mutt-send-email-mst@kernel.org> <20190725094837-mutt-send-email-mst@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.85.160.194 Subject: Re: [Qemu-devel] [PATCH v3 0/4] Introduce the microvm machine type 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: Peter Maydell , Eduardo Habkost , Sergio Lopez , Maran Wilson , Stefan Hajnoczi , QEMU Developers , Gerd Hoffmann , Stefano Garzarella , Richard Henderson Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Thu, Jul 25, 2019 at 04:13:13PM +0200, Paolo Bonzini wrote: > On 25/07/19 15:54, Michael S. Tsirkin wrote: > >> FWIW the "PCI tax" seems to be ~10 ms in QEMU, ~10 ms in the firmware(*) > >> and ~25 ms in the kernel. > > How did you measure the qemu time btw? > > > > It's QEMU startup, but not QEMU altogether. For example the time spent > in memory.c when a BAR is programmed is not part of those 10 ms. > > So I just computed q35 qemu startup - microvm qemu startup, it's 65 vs > 65 ms. > > Paolo Oh so it could be eventfd or whatever, just as well. I actually wonder whether we spend much time within synchronize_* calls. eventfd triggers this a lot of times. How about ioeventfd=off? Does this speed up things? -- MST