系统技术非业余研究

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在作网络程序的时候, 经常需要了解interrupts和软中断的平衡情况, 需要知道每秒有多少中断发生,发生在哪个cpu上.
Linux下中断来源可以从 /proc/interrupts 中了解到:

$ cat /proc/interrupts 
           CPU0       CPU1       
  0:     247701     250313   IO-APIC-edge      timer
  1:        501        567   IO-APIC-edge      i8042
  3:          1          1   IO-APIC-edge    
  8:          1          0   IO-APIC-edge      rtc0
  9:        256        240   IO-APIC-fasteoi   acpi
 12:       1134       1149   IO-APIC-edge      i8042
 16:        629        554   IO-APIC-fasteoi   nvidia
 17:      21313      20869   IO-APIC-fasteoi   firewire_ohci, eth1
 18:          0          0   IO-APIC-fasteoi   mmc0
 19:      51822      50079   IO-APIC-fasteoi   ata_piix, ata_piix
 20:       5605       5255   IO-APIC-fasteoi   ehci_hcd:usb2, uhci_hcd:usb3, uhci_hcd:usb6
 21:          0          0   IO-APIC-fasteoi   uhci_hcd:usb4, uhci_hcd:usb7
 22:         33         33   IO-APIC-fasteoi   ehci_hcd:usb1, uhci_hcd:usb5, uhci_hcd:usb8
 45:        337        247   PCI-MSI-edge      eth0
 46:        441        447   PCI-MSI-edge      hda_intel
NMI:          0          0   Non-maskable interrupts
LOC:     169176     174899   Local timer interrupts
SPU:          0          0   Spurious interrupts
PMI:          0          0   Performance monitoring interrupts
PND:          0          0   Performance pending work
RES:      42289      40236   Rescheduling interrupts
CAL:        154       1076   Function call interrupts
TLB:       5838       5365   TLB shootdowns
TRM:          0          0   Thermal event interrupts
THR:          0          0   Threshold APIC interrupts
MCE:          0          0   Machine check exceptions
MCP:          5          5   Machine check polls
ERR:          1
MIS:          0

软中断可以从/proc/softirqs 了解到:

$ cat /proc/softirqs 
                CPU0       CPU1       
      HI:          0          0
   TIMER:     160508    1170976
  NET_TX:          2          2
  NET_RX:       3303       3165
   BLOCK:      50964      49198
BLOCK_IOPOLL:          0          0
 TASKLET:      24743      24284
   SCHED:      39483      41848
 HRTIMER:         34         40
     RCU:      92193      92592

总的中断次数可以从vmstat或者dstat了解到:

$ vmstat
procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu----
 r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy id wa
 3  0      0  44160 327144 876600    0    0   894   584  458 2295 11  5 70 15

itop提供了更方便的方式了解,作者Hunz在源码里面写:

It’s quite simple but it does its job.

虽然简单,但是适用:

Ubutun下可以这样安装: apt-get install itop

$ itop
INT                NAME          RATE             MAX
  0 [PIC-edge      time]   628 Ints/s     (max:   628)
  1 [PIC-edge      i804]     4 Ints/s     (max:     4)
 17 [PIC-fasteoi   fire]     8 Ints/s     (max:    22)
 19 [PIC-fasteoi   ata_]     1 Ints/s     (max:    14)
 20 [PIC-fasteoi   ehci]    25 Ints/s     (max:    25)
 45 [MSI-edge      eth0]     1 Ints/s     (max:     1)

他会计算每秒每个中断源中断的次数,看起来比较方便.

祝玩的开心!