Re: High interrupt when using 'dd' with Xen DOM0 kernel

[Jean-Edouard Babin <radius%gmail.com@localhost>]

>> Hello,
>>
>> I upgraded from a quite old (november) NetBSD 4.99 i386 to NetBSD 5
>> amd64. (with latest XEN33 packages)
>
> were you using xen33 or xen31 before ?

It was 3.3.0

>> I tried dd if=/dev/zero of=DomU.img bs=1m count=10240 to make a new
>> image to create a domU
>> but this make interrupt to go to 97%
>> CPU states:  1.0% user,  0.0% nice,  0.0% system, 97.1% interrupt,  2.0% idle
>> 0 root    126    0    0K  12M pgdaemon  5:36 76.07% 76.07% [system]
>
> please try
> systat vm
> to see which interrupt rate is high ?

it seems that the highest int. comes from  ioapic0 pin 20

# dmesg | grep ioapi | grep 20
ioapic0 at mainbus0 apid 2: pa 0xfec00000, virtual wire mode, version
20, 24 pins
ioapic0: pin 20 attached to pci3 device 0 INT_A (type 0<type=0> flags
f<pol=3=Act Lo,trig=3=Level>)
ioapic0: pin 20 attached to pci3 device 1 INT_D (type 0<type=0> flags
f<pol=3=Act Lo,trig=3=Level>)
ioapic0: int20 1a9d8<vector=d8,delmode=1,logical,actlo,level,masked,dest=0>
1000000<target=1>
satalink0: using ioapic0 pin 20, event channel 9 for native-PCI interrupt

satalink0 at pci3 dev 0 function 0
tlp0 at pci3 dev 1 function 0: Lite-On 82C169 Ethernet, pass 2.0

I guess that it's INT_D and not INT_A (I don't know if there is a way
to see that as sysstat only report pin number).

Only wd0 is connected to satalink0, so I tried on another harddrive
and did not get the same problem.


    2 users    Load  1.45  0.43  0.16                  Sat May  2 21:54:46

Proc:r  d  s  w     Csw    Trp    Sys   Int   Sof    Flt      PAGING   SWAPPING
     2    12         40            13   453    15      1      in  out   in  out
                                                        ops
   1.0% Sy   0.0% Us   0.0% Ni  98.6% In   0.4% Id    pages
|    |    |    |    |    |    |    |    |    |    |
=%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%                        forks
                                                                          fkppw
           memory totals (in kB)             453 Interrupts               fksvm
          real  virtual     free                 ioapic0 pin 16           pwait
Active  298548   298548   662844                 ioapic0 pin 23           relck
All     338576   338576  2759952               1 ioapic0 pin 19           rlkok
                                             348 ioapic0 pin 20           noram
Namei         Sys-cache     Proc-cache           vcpu0 ioapic0            ndcpy
    Calls     hits    %     hits     %       104 vcpu0 clock              fltcp
       45       44   98                          vcpu0 xenbus             zfod
                                                                          cow
Disks: seeks xfers bytes %busy                                        256 fmin
   wd0          44 2788K   100                                        341 ftarg
   sd0                                                                    itarg
   sd1                                                               1734 wired
   sd2                                                                    pdfre
   sd3                                                                    pdscn
   cd0
   wd1
   wd2
   wd3
   wd4