High Interrupt rate since r279961 on STABLE/10 branch

[Adrian Chadd]

because they're shared. It just doesn't show up by default as nothing
has really claimed the IRQ.

try vmstat -ia ..


-adrian

On 10 June 2015 at 23:19, Ian Smith <smithi at nimnet.asn.au> wrote:
> On Thu, 11 Jun 2015 09:43:15 +0800, Yanhui Shen wrote:
>  > Hi,
>  >
>  > Thanks, it works!
>  >
>  > https://svnweb.freebsd.org/base/head/sys/dev/pci/vga_pci.c?r1=284012&r2=284011&pathrev=284012
>  >
>  >
>  >
>  > 2015-06-11 0:38 GMT+08:00 Adrian Chadd <adrian at freebsd.org>:
>  >
>  > > Hi,
>  > >
>  > > There was an update to freebsd-head a few days ago from hans - it
>  > > disabled PCI interrupts for VGA until a driver claims it.
>  > >
>  > > See if that helps?
>
> I'm glad it does, and can see the interrupt rate on vgapci0 was 173 when
> bad and 4 when good, but I'm completely at a loss to see how that might
> have affected the interrupt rate on uhci3, shown below as 189643 (!)
> when bad and, er, absent when good?
>
> cheers, Ian
>
>  > > > Device: ThinkPad R400 (Product ID: 278225C)
>  > > > CPU: Intel Core 2 Duo processor T6570 (2.1 GHz)
>  > > > GPU: Intel Integrated Graphics 4500MHD
>  > > >
>  > > > Output of "vmstat -i" with r284205 kernel (abnormal):
>  > > > interrupt                    total              rate
>  > > > irq1: atkbd0              1607             1
>  > > > irq9: acpi0                 131958         104
>  > > > irq12: psm0               4281            3
>  > > > irq16: uhci3               239899376  189643
>  > > > irq20: hpet0 uhci0     1426118      1127
>  > > > irq21: uhci1               40315          31
>  > > > irq23: ehci0               33                0
>  > > > irq256: vgapci0          6059           4
>  > > > irq257: em0               49220         38
>  > > > irq258: hdac0            62                0
>  > > > irq260: ahci0:ch0       17217          13
>  > > > irq261: ahci0:ch1       23               0
>  > > > Total                          241576269  190969
>  > > >
>  > > > Output of "vmstat -i" with r279958 kernel (normal):
>  > > > interrupt                          total       rate
>  > > > irq1: atkbd0                       48155          3
>  > > > irq9: acpi0                      1581468        105
>  > > > irq12: psm0                       209484         13
>  > > > irq19: ehci1                       48099          3
>  > > > irq20: hpet0 uhci0              17385585       1156
>  > > > irq21: uhci1                      680884         45
>  > > > irq23: ehci0                          31          0
>  > > > irq256: vgapci0                  2611430        173
>  > > > irq257: em0                      1342009         89
>  > > > irq258: hdac0                     602220         40
>  > > > irq260: ahci0:ch0                 236313         15
>  > > > irq261: ahci0:ch1                     27          0
>  > > > Total                           24745705       1646