Regression? 2.6.0-test4{,-mm5} SMP interrupt distribution according to /proc/interrupts

From: Robert Davies
Date: Fri Sep 05 2003 - 06:38:30 EST


Please personally Cc: to me, for any additional information or responses to
this post, I am not subscribed to kernel list.

Hardware is dual Athlon-MP, AMD762 chipset for most part 2.6.0-test has
performed well for me. I've noticed however according to /proc/interrupts,
CPU0 is getting all the interrupt service action (like when noapic is set),
is this expected?

516rob@ash$ cat proc_interrupts-2.6.0-test4-mm5
+ uname -a
Linux oak 2.6.0-test4-mm5 #2 SMP Thu Sep 4 18:13:52 BST 2003 i686 AMD
Athlon(tm) MP 2000+ AuthenticAMD GNU/Linux
+ cat /proc/interrupts
CPU0 CPU1
0: 354719 93 IO-APIC-edge timer
1: 457 1 IO-APIC-edge i8042
2: 0 0 XT-PIC cascade
8: 52 1 IO-APIC-edge rtc
9: 0 0 IO-APIC-level acpi
12: 20562 1 IO-APIC-edge i8042
14: 6053 1 IO-APIC-edge ide0
16: 7689 1 IO-APIC-level ide2
17: 203 1 IO-APIC-level eth0, mga@PCI:1:5:0
18: 2270 0 IO-APIC-level EMU10K1
19: 0 0 IO-APIC-level ohci-hcd
NMI: 0 0
LOC: 354664 354663
ERR: 0
MIS: 0

The CPU1 numbers don't seem to change, except 0: and LOC:. I have ACPI active
in both Gentoo with vanilla 2.6.0-test, 2.6.0-test-mm5 and 2.4.22, and also
under SuSE with their 2.4.20 kernel, 2.4 and 2.6 are consistent.

/proc/cmdline shows root=/dev/hde5 reboot=warm, using acpi=off option makes no
change in 2.6.

Under 2.4 kernels the interrupts are distributed :

515rob@ash$ cat proc_interrupts-2.4*
CPU0 CPU1
0: 25148 137206 IO-APIC-edge timer
1: 6 1076 IO-APIC-edge keyboard
2: 0 0 XT-PIC cascade
8: 65 153 IO-APIC-edge rtc
9: 0 0 IO-APIC-level acpi
14: 6619 22404 IO-APIC-edge ide0
16: 12 373 IO-APIC-level ide2
17: 192602 49262 IO-APIC-level eth0, eth1
18: 0 0 IO-APIC-level EMU10K1
19: 0 0 IO-APIC-level usb-ohci
NMI: 0 0
LOC: 162293 162274
ERR: 0
MIS: 0
CPU0 CPU1
0: 70700 62464 IO-APIC-edge timer
1: 2210 2328 IO-APIC-edge keyboard
2: 0 0 XT-PIC cascade
8: 92 91 IO-APIC-edge rtc
9: 0 0 IO-APIC-level acpi
14: 2652 934 IO-APIC-edge ide0
16: 8964 8723 IO-APIC-level ide2
17: 1057 1048 IO-APIC-level eth0
NMI: 0 0
LOC: 133097 133096
ERR: 0
MIS: 0

Regards Rob

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