Re: net-snmp-5.4.2.1 snmpd cpu usage 100%

Hello,

Greetings.

Continuing from my below question posted about net-snmp 5.4.2.1 taking 100%
cpu usage on mips HW, i found the problem similar to the problem ID:
"*Inefficient route reading kills snmpd on - ID: 465161*"

Now i see from our debug logs, an open being called for every VLAN/IP
interface created on the server and it repeats and looks like this has taken
most of the cpu usage time.

The snmpd process is in a loop reading from these files and then doing some
operation .. I only grepped for opening files…. Maybe this continuous
looping is consuming cpu too much:

open("/proc/sys/net/ipv4/
neigh/ethrtm1_2_v995/retrans_time_ms", O_RDONLY) = 11
open("/proc/sys/net/ipv4/neigh/ethrtm1_2_v996/retrans_time_ms", O_RDONLY) =
11
open("/proc/sys/net/ipv4/neigh/ethrtm1_2_v997/retrans_time_ms", O_RDONLY) =
11
open("/proc/sys/net/ipv4/neigh/ethrtm1_2_v998/retrans_time_ms", O_RDONLY) =
11
open("/proc/sys/net/ipv4/neigh/ethrtm1_2_v999/retrans_time_ms", O_RDONLY) =
11
open("/proc/sys/net/ipv4/neigh/ethrtm1_2_v1000/retrans_time_ms", O_RDONLY) =
11
open("/proc/stat", O_RDONLY)            = 9
open("/proc/vmstat", O_RDONLY)          = 9
open("/proc/net/snmp", O_RDONLY)        = 9
open("/proc/net/dev", O_RDONLY)         = 9
open("/proc/sys/net/ipv4/neigh/lo/retrans_time_ms", O_RDONLY) = 11
open("/proc/sys/net/ipv4/neigh/eth2/retrans_time_ms", O_RDONLY) = 11
open("/proc/sys/net/ipv4/neigh/eth0/retrans_time_ms", O_RDONLY) = 11
open("/proc/sys/net/ipv4/neigh/ethrtm1_1_v1/retrans_time_ms", O_RDONLY) = 11
open("/proc/sys/net/ipv4/neigh/ethrtm1_1_v2/retrans_time_ms", O_RDONLY) = 11
open("/proc/sys/net/ipv4/neigh/ethrtm1_1_v3/retrans_time_ms", O_RDONLY) = 11
open("/proc/sys/net/ipv4/neigh/ethrtm1_1_v4/retrans_time_ms", O_RDONLY) = 11
open("/proc/sys/net/ipv4/neigh/ethrtm1_1_v5/retrans_time_ms", O_RDONLY) = 11
open("/proc/sys/net/ipv4/neigh/ethrtm1_1_v6/retrans_time_ms", O_RDONLY) = 11
open("/proc/sys/net/ipv4/neigh/ethrtm1_1_v7/retrans_time_ms", O_RDONLY) = 11
open("/proc/sys/net/ipv4/neigh/ethrtm1_1_v8/retrans_time_ms", O_RDONLY) = 11
open("/proc/sys/net/ipv4/neigh/ethrtm1_1_v9/retrans_time_ms", O_RDONLY) = 11
open("/proc/sys/net/ipv4/neigh/ethrtm1_1_v10/retrans_time_ms", O_RDONLY) =
11
open("/proc/sys/net/ipv4/neigh/ethrtm1_1_v11/retrans_time_ms", O_RDONLY) =
11
open("/proc/sys/net/ipv4/neigh/ethrtm1_1_v12/retrans_time_ms", O_RDONLY) =
11
open("/proc/sys/net/ipv4/neigh/ethrtm1_1_v13/retrans_time_ms", O_RDONLY) =
11
open("/proc/sys/net/ipv4/neigh/ethrtm1_1_v14/retrans_time_ms", O_RDONLY) =
11
open("/proc/sys/net/ipv4/neigh/ethrtm1_1_v15/retrans_time_ms", O_RDONLY) =
11
open("/proc/sys/net/ipv4/neigh/ethrtm1_1_v16/retrans_time_ms", O_RDONLY) =
11
open("/proc/sys/net/ipv4/neigh/ethrtm1_1_v17/retrans_time_ms", O_RDONLY) =
11

This needs optimization on the number read/open operation done on the
interfaces as above?

Also from the posted problem ID (*ID: 465161*)status, it looks closed
without any solution being discussed, is it already corrected?
Please let me know in this regard with your suggessions.
Thanks very much.

Best Regards,
Bheemesh





On Sun, Nov 1, 2009 at 9:59 AM, bheemesh v <[email protected]> wrote:

> Hello,
>
> As part of observations i wanted to add that on the mips HW where if large
> number of VLAN's are being configured the IP-MIB has to update the
> ipAddressTable, where in we see such a CPU load of 100%.
>
> On the other mips servers nodes where there are no such large VLAN's being
> configured, we do not see cpu load ans it shows 0%.
>
> Is it something to deal with IP-MIB? or the sub aganet configuration for
> routing?
>
> Kindly let me know.
> Thanks.
>
> Best Regards,
> Bheemesh
>
>
>
>
>
>
> On Fri, Oct 30, 2009 at 10:56 PM, bheemesh v <[email protected]> wrote:
>
>> Hello,
>>
>> Currently we are using the net-snmp-5.4.2.1 version on our linux server,
>> with snmpd running as master agent on x86 environments and as sub-agent on
>> both x86 and mips environments.
>>
>> Now for the sub aganet on x86 cpu usage looks healthy but for the mips
>> snmpd the cpu usage is occupying 100% most of the time.
>>
>> Has such scenario reported in the past in this mailing list (though i did
>> not come across any)? please suggest your inputs.
>>
>> The stratup of the snmpd for mips sub agent is as below:
>> *snmpd -f -C -c /XX/XXX/etc/SS_NetSNMP/snmpd_subagt.conf -Ls 0 -X -I
>> -var_route ipCidrRouteTable inetCidrRouteTable*
>>
>> The *snmpd_subagt.conf * has this details:
>>
>> *agentxSocket tcp:MasterSnmpAgent:705*
>>
>> Please send in your inputs and let me know for any more details needed
>> from my side too.
>>
>> Thanks in advance.
>> Best Regards,
>> Bheemesh
>>
>
>

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