Date: Thu, 22 Apr 2004 17:51:09 +0400 From: "Artem Koutchine" <matrix@itlegion.ru> To: "John Baldwin" <jhb@FreeBSD.org>, <freebsd-hardware@FreeBSD.org> Subject: Re: ACPI floods CPUs with interrupts Message-ID: <009f01c42870$deadb230$0c00a8c0@artem> References: <010501c426db$cc281a10$0c00a8c0@artem> <200404220913.02440.jhb@FreeBSD.org>
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> On Tuesday 20 April 2004 09:31 am, Artem Koutchine wrote: > > I have installed FreeBSd 5.2-RC2 on ASUS P2B-DS > > with 3ware raid controller and DUAL PIII (slot2) 550Mhz. > > Updated motherboard bios to > > the latest bios and after patching the twe driver, so it does not > > show the "PCI parity erro" several times a second. (I think > > it is related to the fact that 3ware 7506 controller is pci 2.2 > > while p2b is pci 2.1). After that i did top and saw that > > 50% of cpu power is wasted on interrupts. I did > > sysstat and :vmstat. It showed that 46700 interrupts per > > second were generated by acpi on irq 20. So, i booted without > > acpi and got 100% cpu idle. The question is: > > How ACPI can generate IRQs? I thought it is just some kind > > of interface and protocol standard, not > a real hardware part which > > can rise irq. Why does it generate so many irqs? May it be related > > to the PCI parity error on twe? > > It is because the ACPI interrupt is programmed incorrectly (due to a buggy > BIOS) and is treated as edge triggered when it is actually level triggered. > You can try updating to -current to see if that fixes it. Cvsupped -current today and built world and installed new kernel. Now it actually detects the interrupt storm and does what it calles 'thottling' to the source of the interrupts. Now i get only 9000 ints per second and it eats abouts 10% of the CPU. I still do not consider it a good idea and i cannot update bios because the latest update was in 2002 and since then asus made no changed to it. So i just did hint.acpi.0.disabled="1" and disabled acpi. Now i have all 100% of cpu to do something usefull. ACPI is a good thing but it is totally broken on all motherboards. Too bad. Artem
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