[CentOS] Balancing IRQs

Jatin Davey

jashokda at cisco.com
Tue Jul 29 06:16:12 UTC 2014


Hi All

I am using the following Linux version for my application:

****************************************
[root at localhost ~]# uname -a
Linux localhost.localdom 2.6.18-164.el5 #1 SMP Thu Sep 3 03:28:30 EDT 
2009 x86_64 x86_64 x86_64 GNU/Linux
****************************************

****************************************
[root at localhost ~]# cat /etc/*release
CentOS release 5.4 (Final)
****************************************

When my application is running on the server i can see only one core 
being used heavily while the other cores are not being used much. My 
application has a major workload is collecting data from the eth0 
interface and then doing a lot of processing with the data in the 
database. So i can say that the Disk I/O and Network I/O are the major 
contributors towards the workload.

from the /proc/interrupts file i can see the following:

****************************************************
[root at localhost ~]# cat /proc/interrupts
            CPU0       CPU1       CPU2       CPU3
   0:   16084980          0          0          0    IO-APIC-edge timer
   1:        141          0          0          0    IO-APIC-edge i8042
   6:          5          0          0          0    IO-APIC-edge floppy
   7:          0          0          0          0    IO-APIC-edge parport0
   8:          0          0          0          0    IO-APIC-edge rtc
   9:          0          0          0          0   IO-APIC-level acpi
  12:        251          0          0          0    IO-APIC-edge i8042
  51:    2410224          0          0          0   IO-APIC-level ioc0
  59:   11358257          0          0          0   IO-APIC-level eth0
NMI:          0          0          0          0
LOC:   16086147   16090336   16090320   16089691
ERR:          0
MIS:          0
****************************************************

 From the above output i can see that all the interrupts are hitting the 
cpu0 and thats why it is used more than any other core in the system.

Can someone please help me in distributing the interrupts across all the 
cores so that all are used which will eventually result in a better 
performance of my system.

Appreciate your response in this regard.

Thanks
Jatin



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