Re: What determines which interrupts are shared under Linux?

From: Roger Heflin
Date: Tue Aug 15 2006 - 10:35:29 EST

Sergei Shtylyov wrote:

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.

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

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