100% cpu load on kvm

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jjost
Posts: 2
Joined: Thu Dec 17, 2015 4:56 pm

100% cpu load on kvm

Post by jjost » Thu Dec 17, 2015 5:04 pm

Hi!,

I am setting up a IRC-Network consisting of 6 Servers. 4 Bare-Metal Hardware and 2 Virtual Machines.
All Servers are RHEL 7.

I am using 3.2.10 built from source.

The Network is up and running, all Servers are connected via SSL and can talk to each other.

Now my problem is that on both virtual machines unrealircd is using 100% of one cpu-core. On the physical hardware there is barely a usage visible. As there are not users currently i guess its a bug. If I strace the process all I see is the text attached down here. It looks like a busy loop. It does it as fast as it can. Do you have an idea what is going wrong?

Code: Select all

read(6, "", 11)                         = 0
read(8, "", 11)                         = 0
read(9, "", 11)                         = 0
read(10, "", 11)                        = 0
read(12, "", 11)                        = 0
read(13, "", 11)                        = 0
read(14, "", 11)                        = 0
read(15, "", 11)                        = 0
read(16, "", 11)                        = 0
read(17, "", 11)                        = 0
read(19, "", 11)                        = 0
read(20, "", 11)                        = 0
poll([{fd=7, events=POLLIN}, {fd=1, events=POLLIN}], 2, 0) = 0 (Timeout)
clock_gettime(CLOCK_MONOTONIC, {6835947, 682318402}) = 0
poll([{fd=17, events=POLLIN}, {fd=14, events=POLLIN}, {fd=12, events=POLLIN}, {fd=7, events=POLLIN}, {fd=6, events=POLLIN}, {fd=5, events=POLLIN}, {fd=4, events=POLLIN}, {fd=3, events=POLLIN}, {fd=2, events=POLLIN}, {fd=1, events=POLLIN}, {fd=1, events=POLLIN}], 11, 1000) = 4 ([{fd=17, revents=POLLIN}, {fd=14, revents=POLLIN}, {fd=12, revents=POLLIN}, {fd=6, revents=POLLIN}])
clock_gettime(CLOCK_MONOTONIC, {6835947, 682389125}) = 0
read(17, "", 11)                        = 0
read(14, "", 11)                        = 0
read(12, "", 11)                        = 0
read(6, "", 11)                         = 0
poll([{fd=2, events=POLLIN}, {fd=3, events=POLLIN}, {fd=4, events=POLLIN}, {fd=5, events=POLLIN}, {fd=6, events=POLLIN}, {fd=7, events=POLLIN}, {fd=8, events=POLLIN}, {fd=9, events=POLLIN}, {fd=10, events=POLLIN}, {fd=11, events=POLLIN}, {fd=12, events=POLLIN}, {fd=13, events=POLLIN}, {fd=14, events=POLLIN}, {fd=15, events=POLLIN}, {fd=16, events=POLLIN}, {fd=17, events=POLLIN}, {fd=19, events=POLLIN}, {fd=20, events=POLLIN}, {fd=1, events=POLLIN}], 19, 1000) = 12 ([{fd=6, revents=POLLIN}, {fd=8, revents=POLLIN}, {fd=9, revents=POLLIN}, {fd=10, revents=POLLIN}, {fd=12, revents=POLLIN}, {fd=13, revents=POLLIN}, {fd=14, revents=POLLIN}, {fd=15, revents=POLLIN}, {fd=16, revents=POLLIN}, {fd=17, revents=POLLIN}, {fd=19, revents=POLLIN}, {fd=20, revents=POLLIN}])
clock_gettime(CLOCK_MONOTONIC, {6835947, 682650996}) = 0
read(6, "", 11)                         = 0
read(8, "", 11)                         = 0
read(9, "", 11)                         = 0
read(10, "", 11)                        = 0
read(12, "", 11)                        = 0
read(13, "", 11)                        = 0
read(14, "", 11)                        = 0
read(15, "", 11)                        = 0
read(16, "", 11)                        = 0
read(17, "", 11)                        = 0
read(19, "", 11)                        = 0
read(20, "", 11)                        = 0

Syzop
UnrealIRCd head coder
Posts: 1864
Joined: Sat Mar 06, 2004 8:57 pm
Location: .nl
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Re: 100% cpu load on kvm

Post by Syzop » Thu Dec 17, 2015 9:09 pm

I haven't heard before about such an issue. Also, many people run UnrealIRCd on virtualized hardware, one way or the other.

More of a general advice: if you're setting up a new network I would suggest using UnrealIRCd 4. The stable 4.0.0 version will be released this month and UnrealIRCd 3.2.x will be phased out over the next 12 months. Also, UnrealIRCd 4 uses a different I/O engine which may very well make a difference.

(Though again, I haven't heard of such an issue before on 3.2.x. It's definitely not normal)

jjost
Posts: 2
Joined: Thu Dec 17, 2015 4:56 pm

Re: 100% cpu load on kvm

Post by jjost » Fri Dec 18, 2015 11:21 am

It does this on both VMs, on two different Hypervisors. (But both are kvms) So I don´t think that is by coincidence.

Its a internal company network. We need to go online asap and running on a "RC" is forbidden by policy. So the 3.2.x is the only one I can work with,unfortunately.
So, any hints?

I *looks* like it has something todo with this asynchronous DNS-lib unreal is using. But I am not a developer.

Syzop
UnrealIRCd head coder
Posts: 1864
Joined: Sat Mar 06, 2004 8:57 pm
Location: .nl
Contact:

Re: 100% cpu load on kvm

Post by Syzop » Fri Dec 18, 2015 11:52 am

If you have encountered a bug and are running the latest UnrealIRCd version (either 3.2.10.5 or 3.2.10.6) then I suggest reporting it on our bug tracker at https://bugs.unrealircd.org/

Borris
Posts: 1
Joined: Mon Feb 08, 2016 5:30 pm

Re: 100% cpu load on kvm

Post by Borris » Wed Feb 10, 2016 11:23 am

jjost wrote:Hi!,

I am setting up a IRC-Network consisting of 6 Servers. 4 Bare-Metal Hardware and 2 Virtual Machines.
All Servers are RHEL 7.

I am using 3.2.10 built from source.

The Network is up and running, all Servers are connected via SSL and can talk to each other.

Now my problem is that on both virtual machines unrealircd is using 100% of one cpu-core. On the physical hardware there is barely a usage visible. As there are not users currently i guess its a bug. If I strace the process all I see is the text attached down here. It looks like a busy loop. It does it as fast as it can. Do you have an idea what is going wrong?
I'm getting 100% cpu use as well and it's causing it to crash as well. Any idea what the problem is?
The 3 Week Diet from https://skinnyexpress.com/the-3-week-diet-review is helpful.

Syzop
UnrealIRCd head coder
Posts: 1864
Joined: Sat Mar 06, 2004 8:57 pm
Location: .nl
Contact:

Re: 100% cpu load on kvm

Post by Syzop » Wed Feb 10, 2016 5:07 pm

UnrealIRCd 3.2.x is being phased out (security fixes only until Dec 31, 2016) so I suggest migrating to UnrealIRCd 4. It uses a rewritten I/O engine so chances are high that you won't have the same issue :)

This (3.2.x) bug was never reported on the bug tracker. The original poster here said he couldn't use UnrealIRCd 4 because it was still a release candidate at that time. 7 days later was the official UnrealIRCd 4 release, so..wouldn't be surprised if he moved to UnrealIRCd 4.

EmmaPop
Posts: 1
Joined: Thu Oct 13, 2016 11:28 am

Re: 100% cpu load on kvm

Post by EmmaPop » Tue Oct 18, 2016 8:51 am

Syzop wrote:UnrealIRCd 3.2.x is being phased out (security fixes only until Dec 31, 2016) so I suggest migrating to UnrealIRCd 4. It uses a rewritten I/O engine so chances are high that you won't have the same issue :)

This (3.2.x) bug was never reported on the bug tracker. The original poster here said he couldn't use UnrealIRCd 4 because it was still a release candidate at that time. 7 days later was the official UnrealIRCd 4 release, so..wouldn't be surprised if he moved to UnrealIRCd 4.
SPot on, i was sure it was a bug and it got resolved with the new version
Find the best review of phenq

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