Date: Wed, 4 May 2011 20:19:23 +0200 From: Daan Vreeken <Daan@vehosting.nl> To: Jack Vogel <jfvogel@gmail.com> Cc: Current@freebsd.org Subject: Re: Interrupt storm with MSI in combination with em1 Message-ID: <201105042019.23899.Daan@vehosting.nl> In-Reply-To: <BANLkTikejvcKezp56pxYW=t5TLUagHxwRw@mail.gmail.com> References: <201105041734.50738.Daan@vehosting.nl> <BANLkTikejvcKezp56pxYW=t5TLUagHxwRw@mail.gmail.com>
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Hi Jack, Wednesday 04 May 2011 19:46:05 Jack Vogel wrote: > Who makes your motherboard? The problem you are having is that MSIX AND > MSI are both failing as em0 comes up, so it falls back to Legacy interrupt > mode, > and must be having some issue with sharing the line, causing the storm. The motherboard is an Asus "P7H55-M". Sorry, I should have mentioned that the dmesg output is from booting with : > > hw.pci.enable_msix="0" > > hw.pci.enable_msi="0" .. in "loader.conf". With those lines in "loader.conf", MSI and MSIX is disabled, both cards work like they should and there is no interrupt storm. With MSI/MSIX enabled, both cards work like they should and I see the counters of the MSI interrupts increase (in small amounts, like they should), but at boot-time an interrupt storm starts on 'legacy' IRQ 16. Because the only difference between disabling/enabling MSI/MSIX seems to be in the way em0/em1 are used, and because 'em1' shares IRQ 16 according to the dmesg, I'm suspecting 'em1' is causing the storm. (But please correct me if I'm wrong :) What can I do to help track this problem down? > > > > According to "dmesg" the following devices share IRQ 16 : > > > > pcib1: <ACPI PCI-PCI bridge> irq 16 at device 1.0 on pci0 > > em0: <Intel(R) PRO/1000 Network Connection 7.2.3> port > > 0xcc00-0xcc1f mem > > 0xf7de0000-0xf7dfffff,0xf7d00000-0xf7d7ffff,0xf7ddc000-0xf7ddffff > > irq 16 at device 0.0 on pci1 > > vgapci0: <VGA-compatible display> port 0xbc00-0xbc07 > > mem 0xf7800000-0xf7bfffff,0xe0000000-0xefffffff irq 16 at > > device 2.0 on > > pci0 > > ehci0: <Intel PCH USB 2.0 controller USB-B> mem > > 0xf7cfa000-0xf7cfa3ff > > irq 16 at device 26.0 on pci0 > > em1: <Intel(R) PRO/1000 Network Connection 7.2.3> port > > 0xec00-0xec1f mem > > 0xf7fe0000-0xf7ffffff,0xf7f00000-0xf7f7ffff,0xf7fdc000-0xf7fdffff > > irq 16 at device 0.0 on pci4 > > pcib4: <ACPI PCI-PCI bridge> irq 16 at device 28.5 on pci0 > > > > During a storm "vmstat -i" shows a rate of about 220.000 interrupts/sec. > > MSI > > interrupt delivery to both 'em0' and 'em1' seems to work correctly during > > a storm, as I see their counters increase normally in the "vmstat -i" > > output. > > > > As only 'em0' and 'em1' seem to be using MSI interrupts, my guess is that > > the > > e1000 driver is causing this problem. Could it be that the driver forgets > > to > > clear/mask legacy interrupts when attaching the MSI interrupts perhaps? > > > > Any tips on how to debug and/or fix this? > > > > > > The full output of "dmesg" can be found here : > > http://vehosting.nl/pub_diffs/dmesg_plantje2_2011_05_04.txt > > > > And the full output of "pciconf -lv" is here : > > http://vehosting.nl/pub_diffs/pciconf_plantje2_2011_05_04.txt > > Regards, -- Daan Vreeken VEHosting http://VEHosting.nl tel: +31-(0)40-7113050 / +31-(0)6-46210825 KvK nr: 17174380
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