From owner-freebsd-virtualization@freebsd.org Sun Jun 11 09:51:37 2017 Return-Path: Delivered-To: freebsd-virtualization@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id D983FC7838A for ; Sun, 11 Jun 2017 09:51:37 +0000 (UTC) (envelope-from freebsd@omnilan.de) Received: from mx0.gentlemail.de (mx0.gentlemail.de [IPv6:2a00:e10:2800::a130]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 7828A856DC for ; Sun, 11 Jun 2017 09:51:37 +0000 (UTC) (envelope-from freebsd@omnilan.de) Received: from mh0.gentlemail.de (mh0.gentlemail.de [IPv6:2a00:e10:2800::a135]) by mx0.gentlemail.de (8.14.5/8.14.5) with ESMTP id v5B9pYMp079619; Sun, 11 Jun 2017 11:51:34 +0200 (CEST) (envelope-from freebsd@omnilan.de) Received: from titan.inop.mo1.omnilan.net (s1.omnilan.de [217.91.127.234]) (using TLSv1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mh0.gentlemail.de (Postfix) with ESMTPSA id 1CF20F76; Sun, 11 Jun 2017 11:51:34 +0200 (CEST) Message-ID: <593D1299.3030402@omnilan.de> Date: Sun, 11 Jun 2017 11:51:21 +0200 From: Harry Schmalzbauer Organization: OmniLAN User-Agent: Mozilla/5.0 (X11; U; FreeBSD i386; de-DE; rv:1.9.2.8) Gecko/20100906 Lightning/1.0b2 Thunderbird/3.1.2 MIME-Version: 1.0 To: Anish CC: "freebsd-virtualization@freebsd.org" Subject: Re: PCIe passthrough really that expensive? References: <59383F5C.8020801@omnilan.de> <593A5AB1.7090301@omnilan.de> In-Reply-To: <593A5AB1.7090301@omnilan.de> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.7 (mx0.gentlemail.de [IPv6:2a00:e10:2800::a130]); Sun, 11 Jun 2017 11:51:34 +0200 (CEST) X-Milter: Spamilter (Reciever: mx0.gentlemail.de; Sender-ip: ; Sender-helo: mh0.gentlemail.de; ) X-BeenThere: freebsd-virtualization@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: "Discussion of various virtualization techniques FreeBSD supports." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 11 Jun 2017 09:51:37 -0000 Bezüglich Harry Schmalzbauer's Nachricht vom 09.06.2017 10:22 (localtime): > Bezüglich Anish's Nachricht vom 08.06.2017 14:35 (localtime): >> Hi Harry, >>> I thought I'd save these expensive VM_Exits by using the passthru path. >> Completely wrong, is it? >> >> It depends on which processor you are using. For example APICv was >> introduced in IvyBridge which enabled h/w assisted localAPIC rather than >> using s/w emulated, bhyve supports it on Intel processors. … > I'm still usign IvyBridge (E3v2) with this "new" machine, but haven't > ever heard/thought about APCIv! It seems APICv is available on IvyBridge-EP (Xeon E5/E7v2) only, not for E3v2 :-( Furthermore, if I didn't miss anything in the datasheets, no currently available E3 Xeon offers local APIC virtualization. Can somebody of the xperts confirm that? … >> Can you run a simple experiment, assign pptdev interrupts to core that's >> not running guest/vcpu? This will reduce #VMEXIT on vcpu which we know >> is expensive. > Interesting approach. But I have no idea how I should assign a PCIe > specific core to a PCIe dev. Is it pptdev specific? The tunables in > device.hints(5) can't be used for that, can they? I wasn't able to find out how to do that. Any hints highly appreciated! -harry