Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S268028AbUIJXXy (ORCPT ); Fri, 10 Sep 2004 19:23:54 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S268030AbUIJXXy (ORCPT ); Fri, 10 Sep 2004 19:23:54 -0400 Received: from the-village.bc.nu ([81.2.110.252]:42418 "EHLO localhost.localdomain") by vger.kernel.org with ESMTP id S268028AbUIJXXl (ORCPT ); Fri, 10 Sep 2004 19:23:41 -0400 Subject: Re: [PATCH] i386 reduce spurious interrupt noise From: Alan Cox To: Chris Wedgwood Cc: "Maciej W. Rozycki" , LKML , Linus Torvalds In-Reply-To: <20040910231052.GA3078@taniwha.stupidest.org> References: <20040902192820.GA6427@taniwha.stupidest.org> <20040910231052.GA3078@taniwha.stupidest.org> Content-Type: text/plain Content-Transfer-Encoding: 7bit Message-Id: <1094854872.18282.29.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.4.6 (1.4.6-2) Date: Fri, 10 Sep 2004 23:21:26 +0100 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1862 Lines: 43 On Sad, 2004-09-11 at 00:10, Chris Wedgwood wrote: > On Fri, Sep 10, 2004 at 11:23:20PM +0200, Maciej W. Rozycki wrote: > > > > - printk (KERN_INFO "APIC error on CPU%d: %02lx(%02lx)\n", > > > + printk (KERN_DEBUG "APIC error on CPU%d: %02lx(%02lx)\n", > > > This should probably be KERN_ERR even. This is a serious condition -- if > > you ever get such a message, then inter-APIC messages get corrupted and > > this affects system's stability. > > These messages are very common on many platforms, infrequent (once > very few days to twice a day at most in my observations) and seemingly > harmless. On a lot of 2.4 boxes they aren't harmless but thats 2.4 IPI messsage handling bugs. People sometimes assume an IPI is delivered once - but its not its delivered "at least once" and when you get a checksum error like on old dual celerons you get replays. They also identify kernel bugs in some other bit combinations so they are useful there too. I'd say this should only go if we are sure 2.6.x handles IPI replay properly and we mask bits off to see if its real news or a retry. > > > - printk("spurious 8259A interrupt: IRQ%d.\n", irq); > > > + printk(KERN_DEBUG "spurious 8259A interrupt: IRQ%d.\n", irq); > > > You may ever get a single message per system boot from this line. > > Sometimes as boot, though often in my experience several minutes after > boot. The IDE layer will generate these naturally as will any other code that happens to clear an IRQ causing event in non IRQ context. Eventually you clear it just as the IRQ is raised, and the pulse causes the error. This should really go. - 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/