Date: Thu, 5 May 2011 01:27:26 +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: <201105050127.26358.Daan@vehosting.nl> In-Reply-To: <BANLkTi=gGqcUiYS6gurZku5ZwjbOp7TrsA@mail.gmail.com> References: <201105041734.50738.Daan@vehosting.nl> <201105050004.31745.Daan@vehosting.nl> <BANLkTi=gGqcUiYS6gurZku5ZwjbOp7TrsA@mail.gmail.com>
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On Thursday 05 May 2011 00:15:43 you wrote: > This all looks completely kosher, what IRQ is the storm on?? IRQ 16. Further down this email there is a list of devices that share the IRQ according to 'dmesg'. > On Wed, May 4, 2011 at 3:04 PM, Daan Vreeken <Daan@vehosting.nl> wrote: > > Hi, > > > > On Wednesday 04 May 2011 20:47:32 Jack Vogel wrote: > > > Will you please set it back to a default and then boot and capture the > > > message for me? > > > > No problem. Here's the output with MSI/MSIX enabled : > > > > http://vehosting.nl/pub_diffs/dmesg_plantje2_with_msix_2011_05_04.txt > > > > I've also added the output of "vmstat -i" a couple of minutes after a > > reboot > > with MSI enabled : > > http://vehosting.nl/pub_diffs/vmstat_i_2011_05_04.txt > > > > Note that in the above "vmstat -i" dump the interrupt storm hasn't > > started yet. For some reason the storm doesn't always start directly at > > boot. I haven't been able (yet) to pinpoint what's triggering it to > > start. > > > > > On Wed, May 4, 2011 at 11:19 AM, Daan Vreeken <Daan@vehosting.nl> wrote: > > > > 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 Thanks, -- Daan Vreeken VEHosting http://VEHosting.nl tel: +31-(0)40-7113050 / +31-(0)6-46210825 KvK nr: 17174380
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