Re: What determines which interrupts are shared under Linux?

[Roger Heflin <rheflin@atipa.com>]

Sergei Shtylyov wrote:
> Hello,
> 
>> I have identified that the disks that are shared on ide2, ide3 do funny
>> things when both are being heavily used (dma_expiry), this is an older 
>> driver versions
>> but I have experienced it before with a lot newer driver, and a bios 
>> adjustment
>> previously fixed a similar issue, so that may be what is needed in 
>> this case also,
>> I am not sure how they fixed it, but I suspect that the setup the 
>> interrupt
>> to not be shared.
> 
>    I doubt that your suspicions are justified.
> 
>>   I have a large number of machines and under heavy loads all
>> seem to duplicate the issue, and it always happens with the disks on 
>> ide2/ide3,
>> never on the disk connected to ide4.
> 
>    BTW, you never named your particular IDE hardware.

NVIDIA, CK804 chipset.

And the disks are on the sata part, and are found as e g and i so if
they are in legacy mode, it would make me suspect that the disks believe
they are on separate channels, and the performance characteristics appear
to confirm that as the disks don't seem to interfere with each other.

> 
>>            CPU0       CPU1       CPU2       CPU3
>>   0:   56616921    5359998    7002142     938817          XT-PIC  timer
>>   1:          8         88         96          0    IO-APIC-edge  i8042
>>   2:          0          0          0          0          XT-PIC  cascade
>>   4:       2091        100        208       2477    IO-APIC-edge  serial
>>   8:          0          0          0          0    IO-APIC-edge  rtc
>>   9:          0          0          0          0   IO-APIC-level  acpi
>>  20:          0          0          0          0   IO-APIC-level  
>> ehci_hcd
>>  21:          0        950     401419     414482   IO-APIC-level  
>> ide4, ohci_hcd
>>  22:       1165    1704243     576247       6796   IO-APIC-level  
>> ide2, ide3
>>  47:      65971          0          0          0   IO-APIC-level  eth0
>> NMI:          1          1          1          1
>> LOC:   69904264   69877733   69879541   69901903
>> ERR:          0
>> MIS:        105
> 
> MBR, Sergei
>