Take a look at the relative interrupt handling below. This is taken
from kernel v2.2.16 running on a dual Pentium2/450 (CPU stepping 2)
system.
# cat /proc/interrupts
CPU0 CPU1
0: 1984627 5267692 IO-APIC-edge timer
1: 0 2 IO-APIC-edge keyboard
2: 0 0 XT-PIC cascade
5: 17424 32802 IO-APIC-edge eth1
8: 0 3 IO-APIC-edge rtc
13: 1 0 XT-PIC fpu
14: 9814 18808 IO-APIC-edge ide0
15: 4000 5248 IO-APIC-edge ide1
17: 22594 26027 IO-APIC-level eth0
NMI: 0
ERR: 0
I'm a little concerned about the obvious bias in favor of having a
given interrupt handled by CPU1. My previous experience (slighly
earlier kernels on a different machine) has been that the interrupt
load is roughly equal on both CPUs.
Is my concern misplaced?
Here's a little more to go on:
# cat /proc/cpuinfo
processor : 0
vendor_id : GenuineIntel
cpu family : 6
model : 5
model name : Pentium II (Deschutes)
stepping : 2
cpu MHz : 448.805
cache size : 512 KB
fdiv_bug : no
hlt_bug : no
sep_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 2
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge
mca cmov pat pse36 mmx fxsr
bogomips : 894.57
processor : 1
vendor_id : GenuineIntel
cpu family : 6
model : 5
model name : Pentium II (Deschutes)
stepping : 2
cpu MHz : 448.805
cache size : 512 KB
fdiv_bug : no
hlt_bug : no
sep_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 2
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge
mca cmov pat pse36 mmx fxsr
bogomips : 894.57
And still more info:
kernel: Linux version 2.2.16 ([EMAIL PROTECTED]) (gcc version
egcs-2.91.66 19990314/Linux (egcs-1.1.2 release)) #1 SMP Sat Jun 10
00:56:48 EST 2000
kernel: Intel MultiProcessor Specification v1.1
kernel: Virtual Wire compatibility mode.
kernel: OEM ID: OEM00000 Product ID: PROD00000000 APIC at: 0xFEE00000
kernel: Processor #0 Pentium(tm) Pro APIC version 17
kernel: Processor #1 Pentium(tm) Pro APIC version 17
kernel: I/O APIC #2 Version 17 at 0xFEC00000.
kernel: Processors: 2
kernel: mapped APIC to ffffe000 (fee00000)
kernel: mapped IOAPIC to ffffd000 (fec00000)
kernel: Detected 448810 kHz processor.
kernel: Console: colour VGA+ 80x25
kernel: Calibrating delay loop... 894.57 BogoMIPS
kernel: Memory: 257944k/262080k available (828k kernel code, 420k
reserved, 2820k data, 68k init)
kernel: Dentry hash table entries: 32768 (order 6, 256k)
kernel: Buffer cache hash table entries: 262144 (order 8, 1024k)
kernel: Page cache hash table entries: 65536 (order 6, 256k)
kernel: Checking 386/387 coupling... OK, FPU using exception 16 error
reporting.
kernel: Checking 'hlt' instruction... OK.
kernel: POSIX conformance testing by UNIFIX
kernel: mtrr: v1.35a (19990819) Richard Gooch ([EMAIL PROTECTED])
kernel: per-CPU timeslice cutoff: 100.11 usecs.
kernel: CPU0: Intel Pentium II (Deschutes) stepping 02
kernel: calibrating APIC timer ...
kernel: ..... CPU clock speed is 448.8159 MHz.
kernel: ..... system bus clock speed is 99.7366 MHz.
kernel: Booting processor 1 eip 2000
kernel: Calibrating delay loop... 894.57 BogoMIPS
kernel: OK.
kernel: CPU1: Intel Pentium II (Deschutes) stepping 02
kernel: Total of 2 processors activated (1789.13 BogoMIPS).
kernel: enabling symmetric IO mode... ...done.
kernel: ENABLING IO-APIC IRQs
kernel: init IO_APIC IRQs
kernel: IO-APIC (apicid-pin) 2-0, 2-18, 2-19, 2-20, 2-21, 2-22, 2-23
not connected.
kernel: number of MP IRQ sources: 21.
kernel: number of IO-APIC #2 registers: 24.
kernel: testing the IO APIC.......................
kernel:
kernel: IO APIC #2......
kernel: .... register #00: 02000000
kernel: ....... : physical APIC id: 02
kernel: .... register #01: 00170011
kernel: ....... : max redirection entries: 0017
kernel: ....... : IO APIC version: 0011
kernel: .... register #02: 00000000
kernel: ....... : arbitration: 00
kernel: .... IRQ redirection table:
kernel: NR Log Phy Mask Trig IRR Pol Stat Dest Deli Vect:
kernel: 00 000 00 1 0 0 0 0 0 0 00
kernel: 01 000 00 0 0 0 0 0 1 1 59
kernel: 02 0FF 0F 0 0 0 0 0 1 1 51
kernel: 03 000 00 0 0 0 0 0 1 1 61
kernel: 04 000 00 0 0 0 0 0 1 1 69
kernel: 05 000 00 0 0 0 0 0 1 1 71
kernel: 06 000 00 0 0 0 0 0 1 1 79
kernel: 07 000 00 0 0 0 0 0 1 1 81
kernel: 08 000 00 0 0 0 0 0 1 1 89
kernel: 09 000 00 0 0 0 0 0 1 1 91
kernel: 0a 000 00 0 0 0 0 0 1 1 99
kernel: 0b 000 00 0 0 0 0 0 1 1 A1
kernel: 0c 000 00 0 0 0 0 0 1 1 A9
kernel: 0d 000 00 1 0 0 0 0 0 0 00
kernel: 0e 000 00 0 0 0 0 0 1 1 B1
kernel: 0f 000 00 0 0 0 0 0 1 1 B9
kernel: 10 0FF 0F 1 1 0 1 0 1 1 C1
kernel: 11 0FF 0F 1 1 0 1 0 1 1 C9
kernel: 12 000 00 1 0 0 0 0 0 0 00
kernel: 13 000 00 1 0 0 0 0 0 0 00
kernel: 14 000 00 1 0 0 0 0 0 0 00
kernel: 15 000 00 1 0 0 0 0 0 0 00
kernel: 16 000 00 1 0 0 0 0 0 0 00
kernel: 17 000 00 1 0 0 0 0 0 0 00
kernel: .................................... done.
kernel: checking TSC synchronization across CPUs: passed.
Thank you.
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