From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964812AbVHOQb7 (ORCPT ); Mon, 15 Aug 2005 12:31:59 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S964824AbVHOQb6 (ORCPT ); Mon, 15 Aug 2005 12:31:58 -0400 Received: from mail23.syd.optusnet.com.au ([211.29.133.164]:8686 "EHLO mail23.syd.optusnet.com.au") by vger.kernel.org with ESMTP id S964812AbVHOQb6 (ORCPT ); Mon, 15 Aug 2005 12:31:58 -0400 From: Con Kolivas To: vatsa@in.ibm.com Subject: Re: [ck] [PATCH] dynamic-tick patch modified for SMP Date: Tue, 16 Aug 2005 02:30:51 +1000 User-Agent: KMail/1.8.2 Cc: tony@atomide.com, tuukka.tikkanen@elektrobit.com, akpm@osdl.org, johnstul@us.ibm.com, linux-kernel@vger.kernel.org, ak@muc.de, george@mvista.com References: <20050812201946.GA5327@in.ibm.com> <200508141018.29668.kernel@kolivas.org> <20050815153541.GA4731@in.ibm.com> In-Reply-To: <20050815153541.GA4731@in.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200508160230.52860.kernel@kolivas.org> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 16 Aug 2005 01:35, Srivatsa Vaddagiri wrote: > On Sun, Aug 14, 2005 at 10:18:28AM +1000, Con Kolivas wrote: > > timers that made no progress until interrupts drove the timers on again. > > I built in both PIT and APIC dyntick mode into the kernel and the default > > in the way I modified the patch is for APIC mode to be used if it's built > > in. After that I modified the values using the sysfs interface at > > /sys/devices/system/dyn_tick/dyn_tick0/. In APIC mode it seems to run > > close to > > Con, > I am observing the reverse problem - my patch does not work in APIC > mode. I am thinking it has to do something with disabling PIT interrupts. > > Have you enabled CONFIG_DYN_TICK_USE_APIC in my patch? yes I already said I tried apic mode, that's the one that works "best" but I suspect that's reflecting the fact that I hardly ever go below 300Hz on this machine except in init 1. Time definitely was lost the longer the machine was running. > What does > /sys/.../dyn_tick0/state show when my patch is working (in APIC mode for > you)? suitable: 1 enabled: 1 apic suitable: 1 using APIC: 1 (remember I wrote the sysfs portion ;) ) > Can you disable CONFIG_DYN_TICK_USE_APIC with my patch and check if > it works? You mean disable it at runtime or not compile it in at all? Disabling it at runtime caused what I described to you as PIT mode (long stalls etc). > Also can you send me 'dmesg | grep APIC' (want to know if your > hardware has local APIC that is enabled by the kernel). ACPI: Local APIC address 0xfee00000 ACPI: LAPIC (acpi_id[0x00] lapic_id[0x00] enabled) Processor #0 15:2 APIC version 20 ACPI: LAPIC (acpi_id[0x01] lapic_id[0x01] enabled) Processor #1 15:2 APIC version 20 ACPI: LAPIC_NMI (acpi_id[0x00] high edge lint[0x1]) ACPI: LAPIC_NMI (acpi_id[0x01] high edge lint[0x1]) ACPI: IOAPIC (id[0x02] address[0xfec00000] gsi_base[0]) IOAPIC[0]: apic_id 2, version 32, address 0xfec00000, GSI 0-23 Enabling APIC mode: Flat. Using 1 I/O APICs mapped APIC to ffffd000 (fee00000) mapped IOAPIC to ffffc000 (fec00000) ENABLING IO-APIC IRQs ACPI: Using IOAPIC for interrupt routing Cheers, Con