From owner-freebsd-testing@FreeBSD.ORG Sun Mar 2 21:41:07 2014 Return-Path: Delivered-To: freebsd-testing@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 2467A140 for ; Sun, 2 Mar 2014 21:41:07 +0000 (UTC) Received: from mail-qc0-f174.google.com (mail-qc0-f174.google.com [209.85.216.174]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id D72141C05 for ; Sun, 2 Mar 2014 21:41:06 +0000 (UTC) Received: by mail-qc0-f174.google.com with SMTP id x13so2954586qcv.19 for ; Sun, 02 Mar 2014 13:41:00 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:sender:in-reply-to:references:from :date:message-id:subject:to:cc:content-type; bh=z15Bd3qBOTkKaXCF9l81M/BoNuViyBHlPoQFSCkeuJs=; b=Bh8914l8x4HNVKp5Du8IcCyA6f0RGd9eMgDDsfBMLLO5LhkacdRGZ/c3N7FHwqso+k VYg2l1bBeSv8s911lqz7do5H4AkHnj76Em3zQwiiaME9u6p2juTavczAUtUGd/Do+wg6 ULkGZXQOUEJbAXSRf3rqJvpR+xc8CmEAfwfPxqHjnKhuyDG9YMbyTCm/+30Zke+RDaB/ eC5lo//7tyjKlXhY+r90XTXnr2knxdTHyn2qbS0GmALOlpfCiuNqarqfFuIGdnxHzCx7 MBHGxiORS07VFn82ZOPh3Hlrr+xO91Bn83WbLV6PaBU6lscyc1gzdAdq7AD1zsOPUxCe dKNw== X-Gm-Message-State: ALoCoQnEDTjcXJXELatF+OJh4GiiPweHtrdFuu29X0dJziigC+DDBAGGur3QW6jebnnYvz+XKJig X-Received: by 10.224.104.2 with SMTP id m2mr5967632qao.3.1393796460597; Sun, 02 Mar 2014 13:41:00 -0800 (PST) MIME-Version: 1.0 Sender: jmmv@meroh.net Received: by 10.96.83.102 with HTTP; Sun, 2 Mar 2014 13:40:40 -0800 (PST) X-Originating-IP: [108.176.158.82] In-Reply-To: References: <20140227081759.GA29517@x2.osted.lan> From: Julio Merino Date: Sun, 2 Mar 2014 16:40:40 -0500 X-Google-Sender-Auth: mp_ZaXKVI5rEpJ87e8I3xGSCOKk Message-ID: Subject: Re: 100% repeatability? To: Alan Somers Content-Type: text/plain; charset=ISO-8859-1 Cc: "freebsd-testing@freebsd.org" , Peter Holm X-BeenThere: freebsd-testing@freebsd.org X-Mailman-Version: 2.1.17 Precedence: list List-Id: Testing on FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 02 Mar 2014 21:41:07 -0000 [ Thread hijack coming! ] On Thu, Feb 27, 2014 at 12:20 PM, Alan Somers wrote: > > If nprocs and maxproc were jail-specific variables, then you could > simply run this test inside of a jail. However, they look global to > me. I think that the only good way to test the feature would be to > run the test inside of a private bhyve instance with an extremely > minimal set of services. That way you could ensure that no unexpected > processes would be started. It would be much more work, though. You > would also need a way to communicate to the guest OS. Perhaps an > emulated serial port? Wow... that sounds like a lot of overhead for an apparently-simple kernel test! I think we should discuss, and possibly document, a recommended way of running kernel-level tests for FreeBSD. We have nothing in this regard and reinventing the wheel for every test without thinking through the various alternatives upfront will be... "ugly" to say the least. Now, I do not have an answer to this. >From previous experience in NetBSD, I think that the "anykernel" design implemented there works very well for these kinds of tests. I do think FreeBSD would benefit from rump immensely, but the problem is that it's a complex thing to do implementation-wise. See http://en.wikipedia.org/wiki/Anykernel and http://wiki.netbsd.org/rumpkernel/ to get started. Without rump, all that is left are jails, bhyve instances and natively-run tests (and maybe something else?). Each has its own problems but are easier to use today than reimplementing rump. Maybe we should attempt to guide developers to one of these three options depending on what they are trying to test and provide helper code to make the setup easy? Or maybe we should investigate whether "porting" rump to FreeBSD would make sense?