[Pkg-net-snmp-devel] Bug#667605: snmpd: The CPU Raw usage reports less than no. cores * 100 percent

[Adrian Ban]

Package: snmpd
Version: 5.4.3-dfsg-2.4
Severity: normal
Tags: upstream

I found a strange CPU Raw usage reports after the upgrade from 5.4.3-dfsg-2.2
to 5.4.3-dfsg-2.4.

Here are 2 SNMP report from 2 different system with 4 cores each:

Good SNMP

# dpkg -l | grep snmp
ii  libsnmp-base                              5.4.3~dfsg-2.2
SNMP (Simple Network Management Protocol) MIBs and documentation
ii  libsnmp15                                 5.4.3~dfsg-2.2
SNMP (Simple Network Management Protocol) library
ii  snmp                                      5.4.3~dfsg-2.2
SNMP (Simple Network Management Protocol) applications
ii  snmpd                                     5.4.3~dfsg-2.2
SNMP (Simple Network Management Protocol) agents

# snmpd -v

NET-SNMP version:  5.4.3
Web:               http://www.net-snmp.org/
Email:             net-snmp-coders at lists.sourceforge.net

CpuRaw output

$ IP=A.A.A.185; COM=YYYY; snmpwalk -v2c -c$COM $IP .1.3.6.1.4.1.2021.11 | grep
"CpuRaw"; echo "wait 10 seconds"; sleep 10; snmpwalk -v2c -c$COM $IP
..1.3.6.1.4.1.2021.11 | grep "CpuRaw"

UCD-SNMP-MIB::ssCpuRawUser.0 = Counter32: 11598955
UCD-SNMP-MIB::ssCpuRawNice.0 = Counter32: 2005
UCD-SNMP-MIB::ssCpuRawSystem.0 = Counter32: 1465887
UCD-SNMP-MIB::ssCpuRawIdle.0 = Counter32: 1732454780
UCD-SNMP-MIB::ssCpuRawWait.0 = Counter32: 917382
UCD-SNMP-MIB::ssCpuRawKernel.0 = Counter32: 0
UCD-SNMP-MIB::ssCpuRawInterrupt.0 = Counter32: 418
UCD-SNMP-MIB::ssCpuRawSoftIRQ.0 = Counter32: 15281275

wait 10 seconds

UCD-SNMP-MIB::ssCpuRawUser.0 = Counter32: 11599129
UCD-SNMP-MIB::ssCpuRawNice.0 = Counter32: 2005
UCD-SNMP-MIB::ssCpuRawSystem.0 = Counter32: 1465888
UCD-SNMP-MIB::ssCpuRawIdle.0 = Counter32: 1732458577
UCD-SNMP-MIB::ssCpuRawWait.0 = Counter32: 917386
UCD-SNMP-MIB::ssCpuRawKernel.0 = Counter32: 0
UCD-SNMP-MIB::ssCpuRawInterrupt.0 = Counter32: 418
UCD-SNMP-MIB::ssCpuRawSoftIRQ.0 = Counter32: 15281301

------------------------
Results:

UCD-SNMP-MIB::ssCpuRawUser.0 = 174
UCD-SNMP-MIB::ssCpuRawNice.0 = 0
UCD-SNMP-MIB::ssCpuRawSystem.0 = 1
UCD-SNMP-MIB::ssCpuRawIdle.0 = 3797
UCD-SNMP-MIB::ssCpuRawWait.0 = 4
UCD-SNMP-MIB::ssCpuRawKernel.0 = 0
UCD-SNMP-MIB::ssCpuRawInterrupt.0 = 0
UCD-SNMP-MIB::ssCpuRawSoftIRQ.0 = 26
Total = 4002
=> 400.20% for 4 cores

400.20% is perfect for 4 cores system.




Bad SNMP

# snmpd -v

NET-SNMP version:  5.4.3
Web:               http://www.net-snmp.org/
Email:             net-snmp-coders at lists.sourceforge.net

# dpkg -l | grep snmp
ii  libsnmp-base                       5.4.3~dfsg-2.4            SNMP (Simple
Network Management Protocol) MIBs and documentation
ii  libsnmp15                          5.4.3~dfsg-2.4            SNMP (Simple
Network Management Protocol) library
ii  snmpd                              5.4.3~dfsg-2.4            SNMP (Simple
Network Management Protocol) agents

CpuRaw output

$ IP=B.B.B.54; COM=YYYY; snmpwalk -v2c -c$COM $IP .1.3.6.1.4.1.2021.11 | grep
"CpuRaw"; echo "wait 10 seconds"; sleep 10; snmpwalk -v2c -c$COM $IP
..1.3.6.1.4.1.2021.11 | grep "CpuRaw"

UCD-SNMP-MIB::ssCpuRawUser.0 = Counter32: 1514372
UCD-SNMP-MIB::ssCpuRawNice.0 = Counter32: 0
UCD-SNMP-MIB::ssCpuRawSystem.0 = Counter32: 4430516
UCD-SNMP-MIB::ssCpuRawIdle.0 = Counter32: 104303480
UCD-SNMP-MIB::ssCpuRawWait.0 = Counter32: 1264773
UCD-SNMP-MIB::ssCpuRawKernel.0 = Counter32: 0
UCD-SNMP-MIB::ssCpuRawInterrupt.0 = Counter32: 401
UCD-SNMP-MIB::ssCpuRawSoftIRQ.0 = Counter32: 44492

wait 10 seconds

UCD-SNMP-MIB::ssCpuRawUser.0 = Counter32: 1514418
UCD-SNMP-MIB::ssCpuRawNice.0 = Counter32: 0
UCD-SNMP-MIB::ssCpuRawSystem.0 = Counter32: 4430658
UCD-SNMP-MIB::ssCpuRawIdle.0 = Counter32: 104307032
UCD-SNMP-MIB::ssCpuRawWait.0 = Counter32: 1264811
UCD-SNMP-MIB::ssCpuRawKernel.0 = Counter32: 0
UCD-SNMP-MIB::ssCpuRawInterrupt.0 = Counter32: 401
UCD-SNMP-MIB::ssCpuRawSoftIRQ.0 = Counter32: 44493

------------------------
Results:

UCD-SNMP-MIB::ssCpuRawUser.0 = 46
UCD-SNMP-MIB::ssCpuRawNice.0 = 0
UCD-SNMP-MIB::ssCpuRawSystem.0 = 142
UCD-SNMP-MIB::ssCpuRawIdle.0 = 3552
UCD-SNMP-MIB::ssCpuRawWait.0 = 38
UCD-SNMP-MIB::ssCpuRawKernel.0 = 0
UCD-SNMP-MIB::ssCpuRawInterrupt.0 = 0
UCD-SNMP-MIB::ssCpuRawSoftIRQ.0 = 1
Total = 3779
=> 377.90% for 4 cores.

But this value is less than 400% for a system with 4 cores. This happen after
the upgrade.