Take the 2-minute tour ×
Server Fault is a question and answer site for professional system and network administrators. It's 100% free, no registration required.

My system is a Debian 6.0.3 x86_64 box w/kernel 2.6.32-5-openvz-amd64, it hosts a number of OpenVZ containers. I have recently migrated from LXC/newer kernel from backports repo to the stable OpenVZ kernel to resolve network issues but got another issue - the CPU spends a lot of time processing software interrupts. Here is a Munin graph for CPU time: http://prntscr.com/arjzl.

I added nohz=off and highres=off to the kernel command line but that did not help much. And, the number of interrupts is quite low on this box according to another Munin graph: http://prntscr.com/ark19, so the interrupts seem to be not the cause of this issue. When I run top, zabbix_server is the most CPU consumer but I don't see any relation between zabbix_server and software interrupts.

I'm not sure how to proceed with investigation, this looks like a kernel bug or a kernel module bug to me, but I don't know hot to track this down to the guilty process/module. Maybe there is another kernel command line parameter to tune. What should I try next?

share|improve this question

1 Answer 1

up vote 3 down vote accepted

zabbix_server is the most CPU consumer but I don't see any relation between zabbix_server and software interrupts.

I wonder how exactly do you try seeing a relation? Have you tried stopping it, for example?

Since this problem has arisen after kernel change, it looks reasonably to assume this is a bug of OVZ 2.6.32-5. I suggest using http://wiki.openvz.org/Download/kernel/rhel6/042stab055.16 if it's fresher than yours current (as it seems).

share|improve this answer
    
Hmm good point, I just tried to stop it and si time was back to normal as soon as I did! So they were related closely. But I just can't get the reason of this relation, zabbix_server is a userspace thing so it should be a bug definitely. I will try to get a newer OpenVZ implementation but it looks like I will have to compile it myself. –  Alex Jun 18 '12 at 17:47
1  
@Alex, You can extract pre-built RPM, they're shipping, to corresponding location and then just use mkinitcpio appropriately. That would save hell-a-lot of work. Also, since you've found zabbix was a bugger, you can as well strace it to see if there's something weird going on. –  poige Jun 18 '12 at 17:53
    
Thank you I'll try this tonight –  Alex Jun 18 '12 at 17:55
1  
@Alex, «zabbix_server is a userspace thing so it should be a bug definitely» — linfo.org/software_interrupt.html : «A software interrupt, also called an exception, is an interrupt that is caused by software, usually by a program in user mode.» –  poige Jun 19 '12 at 2:04
    
RedHat kernel solved my problem! –  Alex Jun 19 '12 at 6:47

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.