Download Red Hat LINUX 7.2 - OFFICIAL LINUX CUSTOMIZATION GUIDE Installation guide

Chapter 2. The /proc File System
28
2.2.9. /proc/interrupts
This file records the number of interrupts per IRQ on the x86 architecture. A standard
/proc/interrupts looks similar to this:
0:
1:
2:
8:
10:
12:
14:
15:
NMI:
ERR:
CPU0
80448940
174412
0
1
410964
60330
1314121
5195422
0
0
XT-PIC
XT-PIC
XT-PIC
XT-PIC
XT-PIC
XT-PIC
XT-PIC
XT-PIC
timer
keyboard
cascade
rtc
eth0
PS/2 Mouse
ide0
ide1
For a multi-processor machine, this file may look slightly different:
CPU0
0: 1366814704
1:
128
2:
0
8:
0
12:
5323
13:
1
16:
11184294
20:
8450043
30:
10432
31:
23
NMI:
0
ERR:
0
CPU1
0
340
0
1
5793
0
15940594
11120093
10722
22
XT-PIC
IO-APIC-edge
XT-PIC
IO-APIC-edge
IO-APIC-edge
XT-PIC
IO-APIC-level
IO-APIC-level
IO-APIC-level
IO-APIC-level
timer
keyboard
cascade
rtc
PS/2 Mouse
fpu
Intel EtherExpress Pro 10/100 Ethernet
megaraid
aic7xxx
aic7xxx
The first column refers to the IRQ number. Each CPU in the system has its own column and its own
number of interrupts per IRQ. The next column tells you the type of interrupt, and the last column
contains the name of the device that is located at that IRQ.
Each of the types of interrupts seen in this file, which are architecture-specific, mean something a little
different. For x86 machines, the following values are common:
• XT-PIC
— The old AT computer interrupts.
— The voltage signal on this interrupt transitions from low to high, creating an
edge, where the interrupt occurs and is only signaled once. This kind of interrupt, as well as the
IO-APIC-level interrupt, are only seen on systems with processors from the 586 family and
higher.
• IO-APIC-edge
• IO-APIC-level
low again.
— Generates interrupts when its voltage signal goes high until the signal goes
2.2.10. /proc/iomem
This file shows you the current map of the system’s memory for its various devices:
00000000-0009fbff
0009fc00-0009ffff
000a0000-000bffff
000c0000-000c7fff
:
:
:
:
System RAM
reserved
Video RAM area
Video ROM