Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261609AbVEJLMs (ORCPT ); Tue, 10 May 2005 07:12:48 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261610AbVEJLMr (ORCPT ); Tue, 10 May 2005 07:12:47 -0400 Received: from ns1.suse.de ([195.135.220.2]:48836 "EHLO mx1.suse.de") by vger.kernel.org with ESMTP id S261609AbVEJLM0 (ORCPT ); Tue, 10 May 2005 07:12:26 -0400 Date: Tue, 10 May 2005 13:12:24 +0200 From: Andi Kleen To: Bernd Paysan Cc: suse-amd64@suse.com, Andi Kleen , linux-kernel@vger.kernel.org Subject: Re: [suse-amd64] False "lost ticks" on dual-Opteron system (=> timer twice as fast) Message-ID: <20050510111223.GH25612@wotan.suse.de> References: <200505081445.26663.bernd.paysan@gmx.de> <20050508134035.GC15724@wotan.suse.de> <200505091253.21252.bernd.paysan@gmx.de> <200505091517.30555.bernd.paysan@gmx.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200505091517.30555.bernd.paysan@gmx.de> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1512 Lines: 43 > I went through the BIOS setup, and found a disabled feature "ACPI 2.0", > which I enabled. Now Linux finds the HPET timer. Great. The machine came like this? I wish OEMs wouldn't do such things... > > # grep -i hpet boot.log > ACPI: HPET (v001 A M I OEMHPET 0x04000518 MSFT 0x00000097) @ > 0x00000000e8ff3c30 > ACPI: HPET id: 0x102282a0 base: 0xfec01000 > time.c: Using 14.318180 MHz HPET timer. > time.c: Using HPET based timekeeping. > hpet0: at MMIO 0xfec01000, IRQs 2, 8, 0 > hpet0: 69ns tick, 3 32-bit timers > hpet_acpi_add: no address or irqs in _CRS > > and everything appears to work (though there's still no designated CPU to > handle the timer interrupts). xntpd syncs quickly, I'm happy (so far ;-). Great. > > So that explains why nobody sees this problem. But the TSC-based fallback > timekeeping is still broken on SMP systems with PowerNow and distributed > IRQ handling, which both together seem to be rare enough ;-). There is a patch pending for the TSC problem - using the pmtimer instead in this case. But the distributed timer interrupt problem is weird. It should not happen. You sure it was IRQ 0 that was duplicated and not "LOC" ? When you watch -n1 cat /proc/interrupts does the rate roughly match up to 1000Hz? -Andi - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/