[Oisf-users] Help with 99% CPU usage

Anoop Saldanha anoopsaldanha at gmail.com
Wed Jun 5 15:30:38 UTC 2013

On Wed, Jun 5, 2013 at 5:04 PM, Victor Julien <lists at inliniac.net> wrote:
> On 06/05/2013 12:34 PM, Anoop Saldanha wrote:
>> On Wed, Jun 5, 2013 at 2:45 PM, Duarte Silva
>> <duarte.silva at serializing.me> wrote:
>>> On Thursday 16 May 2013 10:01:26 Duarte Silva wrote:
>>>> On Wednesday 15 May 2013 19:54:21 Anoop Saldanha wrote:
>>>>> On Wed, May 15, 2013 at 3:55 PM, Duarte Silva
>>>>> <duarte.silva at serializing.me> wrote:
>>>>>> Hi all,
>>>>>> I'm currently facing a problem with Suricata. After running for a while,
>>>>>> there is always an AF_PACKET thread (workers mode) that hogs the CPU to
>>>>>> which it is bound to creating an awful amount of packet loss. I have
>>>>>> discarded the>
>>>>>> following factors:
>>>>>>  - Number of rules, it has also happened without rules;
>>>>>>  - Amount of network traffic, I have seen Suricata handle ~18 MBs (150
>>>>>>  MBps) of>
>>>>>> traffic without problems with the current configuration and it as also
>>>>>> happened with only ~2 MBs of traffic;
>>>>>>  - Memory, Suricata was only using ~500 MB of it when the CPU usage
>>>>>>  pegged
>>>>>>  to>
>>>>>> 100%;
>>>>>> This happens repeatedly and after it happens, Suricata takes a long time
>>>>>> to
>>>>>> stop. Could some tell me what I can do to debug this issue?
>>>>>> Suricata is executed with the following command line:
>>>>>> suricata -D -c /etc/suricata/suricata.yaml --pidfile
>>>>>> /var/lock/subsys/suricata --af-packet=eth1 --user=suri --group=suri
>>>>>> I have also attached any files that can help out in debugging.
>>>>> While this thread hogs the cpu, can you attach gdb to the suricata
>>>>> process, and get a bt for the specified thread, and also all the
>>>>> threads.
>>>> Follows in the attachments the traces for the hogging thread (I had to wait
>>>> almost height hours for it to happen). I have created three traces in
>>>> different times while the AFPacketeth12 was hoging the CPU, all of them end
>>>> up in the list_array_get in dslib.c.
>>>> I will investigate what is happening by looking at the code, when it happens
>>>> again I will also take traces for the other threads.
>>> Hi,
>>> I have taken two more traces when it happened again. Could you please give a
>>> little help on this? I think it has something to do with HTTP processing.
>> @Duarte
>> What version of suricata are you running?
>> @Victor.
>> From the last bt that Duarte sent, it looks like the list has grown in
>> size.  The size is around 4k.  Probably that's the reason for the
>> slowdown?  Every time we inspect state we will end up looping through
>> the whole array.
> Looks like it ya. The array approach doesn't really seem to scale that
> well. Maybe a optimization in the short run would be to walk it
> backwards? If we have this many TX' we probably still only have the last
> few active.

Yeah, that should be the short term solution I think.  Let me look into it.

Anoop Saldanha

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