From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262844AbTLIFDP (ORCPT ); Tue, 9 Dec 2003 00:03:15 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262848AbTLIFDO (ORCPT ); Tue, 9 Dec 2003 00:03:14 -0500 Received: from 216-229-91-229-empty.fidnet.com ([216.229.91.229]:41477 "EHLO mail.icequake.net") by vger.kernel.org with ESMTP id S262844AbTLIFDJ (ORCPT ); Tue, 9 Dec 2003 00:03:09 -0500 Date: Mon, 8 Dec 2003 23:03:08 -0600 From: Ryan Underwood To: linux-kernel@vger.kernel.org Subject: Re: APIC support on Slot-A Athlon, K6 [PATCH] Message-ID: <20031209050308.GA10763@dbz.icequake.net> References: <200312081707.hB8H7B85014403@harpo.it.uu.se> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="jy6Sn24JjFx/iggw" Content-Disposition: inline In-Reply-To: <200312081707.hB8H7B85014403@harpo.it.uu.se> User-Agent: Mutt/1.5.4i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org --jy6Sn24JjFx/iggw Content-Type: multipart/mixed; boundary="LyciRD1jyfeSSjG0" Content-Disposition: inline --LyciRD1jyfeSSjG0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Dec 08, 2003 at 06:07:11PM +0100, Mikael Pettersson wrote: > On Mon, 8 Dec 2003 05:58:59 -0600, Ryan Underwood wrote: > >> Furthermore, I/O-APIC usage requires (in hardware) that the > >> processor has a local APIC. > > > >What can the APIC support alone accomplish, without an I/O-APIC? > >Just NMI watchdog and related things? (looking at CONFIG_APIC help) > >Looks like I/O-APIC is the real desired feature, but a functioning local > >APIC, though not very useful by itself, is a prerequisite for it. >=20 > Local APIC gives you: > - using the local APIC timer instead of the mobo's legacy timer > - thermal management interrupts on P4s (dunno about K7s/K8s) > - performance counter interrupts, which can be used as an NMI > source (watchdog, profiling) or for performance analysis >=20 > I/O-APIC gives you: > - more interrupt vectors =3D=3D> less IRQ sharing =3D=3D> improved > stability and performance > - lower-overhead interrupt management > - I/O-APIC NMI watchdog (another timer with NMI delivery mode) I attached a Kconfig patch more explicitly stating the prerequisites for using the I/O-APIC. --=20 Ryan Underwood, --LyciRD1jyfeSSjG0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: attachment; filename="kconfig.diff" Content-Transfer-Encoding: quoted-printable --- arch/i386/Kconfig.bak 2003-08-08 23:32:43.000000000 -0500 +++ arch/i386/Kconfig 2003-12-08 23:00:36.000000000 -0600 @@ -491,6 +491,10 @@ If you have a system with several CPUs, you do not need to say Y here: the IO-APIC will be used automatically. =20 + A functioning local APIC is a prerequisite for using the I/O-APIC + on uniprocessor machines. Sometimes working ACPI support is also + required (depending on the BIOS implementation). + config X86_LOCAL_APIC bool depends on !SMP && X86_UP_APIC --LyciRD1jyfeSSjG0-- --jy6Sn24JjFx/iggw Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.3 (GNU/Linux) iD8DBQE/1VeMIonHnh+67jkRAvEtAJ9A8iafkFuFA3G05SwRLhDt2Ke9ewCdEVn4 Vz5lQhApEz6+4cKJrV2A5Lk= =P2y0 -----END PGP SIGNATURE----- --jy6Sn24JjFx/iggw--