From owner-freebsd-current@FreeBSD.ORG Tue Feb 28 15:18:28 2012 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 1B893106566B; Tue, 28 Feb 2012 15:18:28 +0000 (UTC) (envelope-from jhb@freebsd.org) Received: from cyrus.watson.org (cyrus.watson.org [65.122.17.42]) by mx1.freebsd.org (Postfix) with ESMTP id E66208FC0C; Tue, 28 Feb 2012 15:18:27 +0000 (UTC) Received: from bigwig.baldwin.cx (bigwig.baldwin.cx [96.47.65.170]) by cyrus.watson.org (Postfix) with ESMTPSA id 9F15246B39; Tue, 28 Feb 2012 10:18:27 -0500 (EST) Received: from jhbbsd.localnet (unknown [209.249.190.124]) by bigwig.baldwin.cx (Postfix) with ESMTPSA id E0FE0B969; Tue, 28 Feb 2012 10:18:26 -0500 (EST) From: John Baldwin To: freebsd-current@freebsd.org Date: Tue, 28 Feb 2012 08:44:22 -0500 User-Agent: KMail/1.13.5 (FreeBSD/8.2-CBSD-20110714-p10; KDE/4.5.5; amd64; ; ) References: <4F26CC5A.2070501@FreeBSD.org> <4F4B5ED3.5090508@FreeBSD.org> <65B1891F-9079-4948-BF37-8A50B4E85071@samsco.org> In-Reply-To: <65B1891F-9079-4948-BF37-8A50B4E85071@samsco.org> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <201202280844.22142.jhb@freebsd.org> X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.2.7 (bigwig.baldwin.cx); Tue, 28 Feb 2012 10:18:27 -0500 (EST) Cc: Andriy Gapon Subject: Re: revisiting tunables under Safe Mode menu option X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 28 Feb 2012 15:18:28 -0000 On Monday, February 27, 2012 2:03:21 pm Scott Long wrote: > > On Feb 27, 2012, at 3:45 AM, Andriy Gapon wrote: > > > on 30/01/2012 18:59 Andriy Gapon said the following: > >> > >> First, I think that this proposal/discussion could have been more useful before > >> the 9.0. Maybe the RE would be interested in adding another item to their > >> pre-release checklist: ask developers about what could be dropped and what should > >> be added to the Safe Mode settings in a new (.0) release. Probably the developers > >> should keep the Safe Mode in mind too when adding new features or making other > >> drastic changes, but the reminder should be welcome. > > [snip] > >> o Since we have a separate ACPI option and because ACPI now is almost a mandatory > >> thing (and not a significant source of boot troubles), maybe we could remove the > >> code that automatically disables ACPI in Safe Mode? > >> > >> o hint.apic.0.disabled - APIC code doesn't seem to be a significant source of boot > >> troubles, like ACPI it has become almost a mandatory thing. So maybe we should > >> remove this setting? > > Turning off the APIC turns off SMP in a very efficient, clean manner. I added this not to isolate the APIC code, but to turn off SMP. That's why it's there, and I'd like the ability to turn off SMP to stay there in some form. If there's a better way to disable SMP that doesn't get into problems with interrupt delivery, then please propose it. As for it being mandatory, it's really only mandatory for MSI these days, though it used to be required for more complex PCIX topologies. You want APIC for other things as well (hwpmc(4) requires it, as do CMCI interrupts, and we really do like to make use of the local APIC timer). > > [dropped proposals snipped] > >> o hw.eisa_slot - Looks like something from ancient times. Probably just > >> irrelevant for most systems. > >> > > This turns off probes in the ISA ioport space that used to cause problems. Why get rid of it? Is its presence causing you problems? I agree this should probably stay. -- John Baldwin