# High interrupt rate Intel mobo DQ57TM - workaround



## bsd3000 (Aug 19, 2013)

Hi staff*.*

I have many systems with INTEL DQ57TM motherboards and 8.2-RELEASE-p9 and something of that has IRQ rate problems.

As you can see:

```
[CMD]vmstat -i[/CMD]
interrupt                          total       rate
irq16: ehci0               5593560975283     218059
irq19: atapci1                1859170078         72
irq23: ehci1                    51303168          2
cpu0: timer                  51303136367       2000
irq256: em0                  22273614942        868
cpu1: timer                  51303136241       2000
cpu2: timer                  51303136241       2000
cpu3: timer                  51303136241       2000
Total                      5822957608561     227002
```


```
PID USERNAME PRI NICE   SIZE    RES STATE   C   TIME   WCPU COMMAND
   11 root     171 ki31     0K    64K CPU3    3 6938.8 100.00% {idle: cpu3}
   11 root     171 ki31     0K    64K RUN     1 6555.8 100.00% {idle: cpu1}
   11 root     171 ki31     0K    64K CPU0    0 6727.4 98.10% {idle: cpu0}
   11 root     171 ki31     0K    64K CPU2    2 4903.6 66.16% {idle: cpu2}
   12 root     -64    -     0K   256K WAIT    2 2173.9 38.77% {irq16: ehci0}
```

(I read many threads in this forum about ehci0 problems and a PR on freebsd FreeBSD's bugtrack systems but not one solves my situation*.*)

I can't recompile the kernel*.* I can't do the upgrade to 8.3 or 9.x so  I played with sysctl (in loader.conf) and BIOS changes but none worked*.* After several tests I found a workaround*.*  If I boot the system WITHOUT VGA and USB keyboard connected, I can see:


```
PID USERNAME PRI NICE   SIZE    RES STATE   C   TIME   WCPU COMMAND
   11 root     171 ki31     0K    64K RUN     0  55:38 96.00% {idle: cpu0}
   11 root     171 ki31     0K    64K CPU2    2  56:02 95.46% {idle: cpu2}
   11 root     171 ki31     0K    64K CPU1    1  55:17 94.68% {idle: cpu1}
   11 root     171 ki31     0K    64K CPU3    3  55:51 89.45% {idle: cpu3}
 4637     89    48    0 11808K  6880K getblk  2   0:29 11.08% imapd
```
and

```
[CMD]ms4# vmstat -i[/CMD]
interrupt                          total       rate
irq16: ehci0                           2          0
irq19: atapci1                   1056444        297
irq23: ehci1                           2          0
cpu0: timer                      7104349       1999
irq256: em0                       266398         74
cpu1: timer                      7104231       1999
cpu2: timer                      7104230       1999
cpu3: timer                      7104230       1999
Total                           29739886       8370
```

It seems to work! But if I connect VGA or keyboard, the IRQ percentage fires up to 50% and I need to reboot to remove this state*.*

I hope this message can be a (little) help for someone*.*

See you*.*


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