CheckMK showing incorrect output for cpu cores and processes

Troubleshooting
, ,
1

CMK version: 2.3.0p41
OS version: Debian 11

Error message: The concerned Windows servers have 2 CPUs × 36 cores & 72 logical processors as shown below -
DeviceID NumberOfCores NumberOfLogicalProcessors
CPU0 36 72
CPU1 36 72

But checkmk is showing no. of processes as 64 in one server and 16 in another server, even though both servers are identical. (refer snippets)

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Output of “cmk --debug -vvn hostname”: (If it is a problem with checks or plugins)

OMD[sitename]:~$ cmk --debug -vvn app-rbg
value store: synchronizing
Trying to acquire lock on /omd/sites/sitename/tmp/check_mk/counters/app-rbg
Got lock on /omd/sites/sitename/tmp/check_mk/counters/app-rbg
value store: loading from disk
Releasing lock on /omd/sites/sitename/tmp/check_mk/counters/app-rbg
Released lock on /omd/sites/sitename/tmp/check_mk/counters/app-rbg
Checkmk version 2.3.0p41

  • FETCHING DATA
    Source: SourceInfo(hostname=‘app-rbg’, ipaddress=‘app-rbg.int.osram-light.com’, ident=‘agent’, fetcher_type=<FetcherType.TCP: 8>, source_type=<SourceType.HOST: 1>)
    [cpu_tracking] Start [7f93c8d2e030]
    Read from cache: AgentFileCache(app-rbg, path_template=/omd/sites/sitename/tmp/check_mk/cache/{hostname}, max_age=MaxAge(checking=0, discovery=90.0, inventory=90.0), simulation=False, use_only_cache=False, file_cache_mode=6)
    Not using cache (Too old. Age is 12 sec, allowed is 0 sec)
    Connecting via TCP to app-rbg.int.osram-light.com:6556 (5.0s timeout)
    Detected transport protocol: TransportProtocol.TLS
    Reading data from agent via TLS socket
    Reading data from agent
    Detected transport protocol: TransportProtocol.MD5
    Try to decrypt output
    Closing TCP connection to app-rbg.int.osram-light.com:6556
    Write data to cache file /omd/sites/sitename/tmp/check_mk/cache/app-rbg
    Trying to acquire lock on /omd/sites/sitename/tmp/check_mk/cache/app-rbg
    Got lock on /omd/sites/sitename/tmp/check_mk/cache/app-rbg
    Releasing lock on /omd/sites/sitename/tmp/check_mk/cache/app-rbg
    Released lock on /omd/sites/sitename/tmp/check_mk/cache/app-rbg
    [cpu_tracking] Stop [7f93c8d2e030 - Snapshot(process=posix.times_result(user=0.029999999999999805, system=0.0, children_user=0.0, children_system=0.0, elapsed=0.9800000004470348))]
    Source: SourceInfo(hostname=‘app-rbg’, ipaddress=‘app-rbg.int.osram-light.com’, ident=‘piggyback’, fetcher_type=<FetcherType.PIGGYBACK: 4>, source_type=<SourceType.HOST: 1>)
    [cpu_tracking] Start [7f93ca034ef0]
    Read from cache: NoCache(app-rbg, path_template=/dev/null, max_age=MaxAge(checking=0.0, discovery=0.0, inventory=0.0), simulation=False, use_only_cache=False, file_cache_mode=1)
    No piggyback files for ‘app-rbg’. Skip processing.
    No piggyback files for ‘app-rbg.int.osram-light.com’. Skip processing.
    Get piggybacked data
    [cpu_tracking] Stop [7f93ca034ef0 - Snapshot(process=posix.times_result(user=0.0, system=0.0, children_user=0.0, children_system=0.0, elapsed=0.0))]
    [cpu_tracking] Start [7f93ca3a2f30]
  • PARSE FETCHER RESULTS
    <<<check_mk>>> / Transition NOOPParser → HostSectionParser
    <<<cmk_agent_ctl_status:sep(0)>>> / Transition HostSectionParser → HostSectionParser
    <<<wmi_cpuload:sep(124)>>> / Transition HostSectionParser → HostSectionParser
    <<>> / Transition HostSectionParser → HostSectionParser
    <<>> / Transition HostSectionParser → HostSectionParser
    <<fileinfo:sep(124)>> / Transition HostSectionParser → HostSectionParser
    <<<winperf_phydisk>>> / Transition HostSectionParser → HostSectionParser
    <<<winperf_if>>> / Transition HostSectionParser → HostSectionParser
    <<<winperf_processor>>> / Transition HostSectionParser → HostSectionParser
    <<>> / Transition HostSectionParser → HostSectionParser
    <<df:sep(9)>> / Transition HostSectionParser → HostSectionParser
    <<<checkmk_agent_plugins_win:sep(0)>>> / Transition HostSectionParser → HostSectionParser
    <<<dotnet_clrmemory:sep(124)>>> / Transition HostSectionParser → HostSectionParser
    <<<wmi_webservices:sep(124)>>> / Transition HostSectionParser → HostSectionParser
    <<>> / Transition HostSectionParser → HostSectionParser
    <<ps:sep(9)>> / Transition HostSectionParser → HostSectionParser
    Transition HostSectionParser → NOOPParser
    <<<cmk_update_agent_status:cached(1773229736,3600):sep(0)>>> / Transition NOOPParser → HostSectionParser
    Transition HostSectionParser → NOOPParser
    <<>> / Transition NOOPParser → HostSectionParser
    HostKey(hostname=‘app-rbg’, source_type=<SourceType.HOST: 1>) → Add sections: [‘check_mk’, ‘checkmk_agent_plugins_win’, ‘cmk_agent_ctl_status’, ‘cmk_update_agent_status’, ‘df’, ‘dotnet_clrmemory’, ‘fileinfo’, ‘logwatch’, ‘mem’, ‘ps’, ‘services’, ‘systemtime’, ‘uptime’, ‘winperf_if’, ‘winperf_phydisk’, ‘winperf_processor’, ‘wmi_cpuload’, ‘wmi_webservices’]
    HostKey(hostname=‘app-rbg’, source_type=<SourceType.HOST: 1>) → Add sections:
    Received no piggyback data
    CPU utilization Total CPU: 1.12%
    Check_MK Agent Version: 2.3.0p41, OS: windows, Last update: 2026-03-10 11:16:54, Agent plug-ins: 1, Local checks: 0
    Disk IO SUMMARY Read: 0.00 B/s, Write: 72.0 kB/s, Latency: 58 microseconds
    Filesystem C:/ Used: 22.70% - 116 GiB of 512 GiB (warn/crit at 92.16%/94.77% used), trend per 1 day 0 hours: +138 MiB, trend per 1 day 0 hours: +0.03%, Time left until disk full: 8 years 14 days
    Filesystem D:/ Used: 1.13% - 34.7 GiB of 2.99 TiB (warn/crit at 94.52%/96.34% used), trend per 1 day 0 hours: -315 MiB, trend per 1 day 0 hours: -0.01%
    Interface Intel[R] Ethernet 25G 2P E810-XXV OCP [1], (up), MAC: B4:83:51:05:FE:D1, Speed: 25 GBit/s, In: 708 B/s (<0.01%), Out: 402 B/s (<0.01%)
    Interface Intel[R] Ethernet 25G 2P E810-XXV OCP 2 [2], (up), MAC: B4:83:51:05:FE:D0, Speed: 25 GBit/s, In: 4.53 kB/s (<0.01%), Out: 4.16 kB/s (<0.01%)
    Interface Remote NDIS Compatible Device [4], (up), MAC: B4:45:06:F0:BC:30, Speed: 426 MBit/s, In: 8.66 B/s (<0.01%), Out: 6.64 B/s (<0.01%)
    Memory and pagefile RAM: 7.49% - 19.1 GiB of 255 GiB, Virtual memory: 7.82% - 22.9 GiB of 293 GiB
    Processor Queue 15 min load: 0.00, 15 min load per core: 0.00 (144 logical cores)
    Service Summary Autostart services: 84, Stopped services: 5
    System Time Offset: -1 second
    Uptime Up since 2026-02-02 04:24:58, Uptime: 37 days 9 hours
    Web Service Default Web Site Connections: 0
    No piggyback files for ‘app-rbg’. Skip processing.
    No piggyback files for ‘app-rbg.int.osram-light.com’. Skip processing.
    [cpu_tracking] Stop [7f93ca3a2f30 - Snapshot(process=posix.times_result(user=0.3599999999999999, system=0.040000000000000036, children_user=0.0, children_system=0.0, elapsed=0.4100000001490116))]
    [agent] Success, [piggyback] Success (but no data found for this host), execution time 1.4 sec | execution_time=1.390 user_time=0.390 system_time=0.040 children_user_time=0.000 children_system_time=0.000 cmk_time_agent=0.950
    OMD[sitename]:~$
    OMD[sitename2]:~$ cmk --debug -vvn app-klm
    value store: synchronizing
    Trying to acquire lock on /omd/sites/sitename2/tmp/check_mk/counters/app-klm
    Got lock on /omd/sites/sitename2/tmp/check_mk/counters/app-klm
    value store: loading from disk
    Releasing lock on /omd/sites/sitename2/tmp/check_mk/counters/app-klm
    Released lock on /omd/sites/sitename2/tmp/check_mk/counters/app-klm
    Checkmk version 2.3.0p41
  • FETCHING DATA
    Source: SourceInfo(hostname=‘app-klm’, ipaddress=‘app-klm.int.osram-light.com’, ident=‘agent’, fetcher_type=<FetcherType.TCP: 8>, source_type=<SourceType.HOST: 1>)
    [cpu_tracking] Start [7f886b324170]
    Read from cache: AgentFileCache(app-klm, path_template=/omd/sites/sitename2/tmp/check_mk/cache/{hostname}, max_age=MaxAge(checking=0, discovery=90.0, inventory=90.0), simulation=False, use_only_cache=False, file_cache_mode=6)
    Not using cache (Too old. Age is 18 sec, allowed is 0 sec)
    Connecting via TCP to app-klm.int.osram-light.com:6556 (5.0s timeout)
    Detected transport protocol: TransportProtocol.TLS
    Reading data from agent via TLS socket
    Reading data from agent
    Detected transport protocol: TransportProtocol.MD5
    Try to decrypt output
    Closing TCP connection to app-klm.int.osram-light.com:6556
    Write data to cache file /omd/sites/sitename2/tmp/check_mk/cache/app-klm
    Trying to acquire lock on /omd/sites/sitename2/tmp/check_mk/cache/app-klm
    Got lock on /omd/sites/sitename2/tmp/check_mk/cache/app-klm
    Releasing lock on /omd/sites/sitename2/tmp/check_mk/cache/app-klm
    Released lock on /omd/sites/sitename2/tmp/check_mk/cache/app-klm
    [cpu_tracking] Stop [7f886b324170 - Snapshot(process=posix.times_result(user=0.03000000000000025, system=0.009999999999999981, children_user=0.0, children_system=0.0, elapsed=1.2100000008940697))]
    Source: SourceInfo(hostname=‘app-klm’, ipaddress=‘app-klm.int.osram-light.com’, ident=‘piggyback’, fetcher_type=<FetcherType.PIGGYBACK: 4>, source_type=<SourceType.HOST: 1>)
    [cpu_tracking] Start [7f886b7cfe60]
    Read from cache: NoCache(app-klm, path_template=/dev/null, max_age=MaxAge(checking=0.0, discovery=0.0, inventory=0.0), simulation=False, use_only_cache=False, file_cache_mode=1)
    No piggyback files for ‘app-klm’. Skip processing.
    No piggyback files for ‘app-klm.int.osram-light.com’. Skip processing.
    Get piggybacked data
    [cpu_tracking] Stop [7f886b7cfe60 - Snapshot(process=posix.times_result(user=0.0, system=0.0, children_user=0.0, children_system=0.0, elapsed=0.0))]
    [cpu_tracking] Start [7f886b326a20]
  • PARSE FETCHER RESULTS
    <<<check_mk>>> / Transition NOOPParser → HostSectionParser
    <<<cmk_agent_ctl_status:sep(0)>>> / Transition HostSectionParser → HostSectionParser
    <<<wmi_cpuload:sep(124)>>> / Transition HostSectionParser → HostSectionParser
    <<>> / Transition HostSectionParser → HostSectionParser
    <<>> / Transition HostSectionParser → HostSectionParser
    <<fileinfo:sep(124)>> / Transition HostSectionParser → HostSectionParser
    <<<winperf_phydisk>>> / Transition HostSectionParser → HostSectionParser
    <<<winperf_if>>> / Transition HostSectionParser → HostSectionParser
    <<<winperf_processor>>> / Transition HostSectionParser → HostSectionParser
    <<>> / Transition HostSectionParser → HostSectionParser
    <<df:sep(9)>> / Transition HostSectionParser → HostSectionParser
    <<<checkmk_agent_plugins_win:sep(0)>>> / Transition HostSectionParser → HostSectionParser
    <<<dotnet_clrmemory:sep(124)>>> / Transition HostSectionParser → HostSectionParser
    <<>> / Transition HostSectionParser → HostSectionParser
    <<ps:sep(9)>> / Transition HostSectionParser → HostSectionParser
    Transition HostSectionParser → NOOPParser
    <<<cmk_update_agent_status:cached(1773229830,3600):sep(0)>>> / Transition NOOPParser → HostSectionParser
    Transition HostSectionParser → NOOPParser
    <<>> / Transition NOOPParser → HostSectionParser
    HostKey(hostname=‘app-klm’, source_type=<SourceType.HOST: 1>) → Add sections: [‘check_mk’, ‘checkmk_agent_plugins_win’, ‘cmk_agent_ctl_status’, ‘cmk_update_agent_status’, ‘df’, ‘dotnet_clrmemory’, ‘fileinfo’, ‘logwatch’, ‘mem’, ‘ps’, ‘services’, ‘systemtime’, ‘uptime’, ‘winperf_if’, ‘winperf_phydisk’, ‘winperf_processor’, ‘wmi_cpuload’]
    HostKey(hostname=‘app-klm’, source_type=<SourceType.HOST: 1>) → Add sections:
    Received no piggyback data
    CPU utilization Total CPU: 1.94%
    Check_MK Agent Version: 2.3.0p41, OS: windows, Last update: 2026-03-10 11:16:54, Agent plug-ins: 1, Local checks: 0
    Disk IO SUMMARY Read: 0.00 B/s, Write: 1.70 MB/s, Latency: 63 microseconds
    Filesystem C:/ Used: 41.00% - 211 GiB of 516 GiB (warn/crit at 92.17%/94.78% used), trend per 1 day 0 hours: -156 MiB, trend per 1 day 0 hours: -0.03%
    Filesystem D:/ Used: 85.54% - 2.56 TiB of 2.99 TiB (warn/crit at 94.52%/96.34% used), trend per 1 day 0 hours: -1.59 GiB, trend per 1 day 0 hours: -0.05%
    Interface Intel[R] Ethernet 25G 2P E810-XXV OCP [4], (up), MAC: B4:83:51:0B:99:B1, Speed: 25 GBit/s, In: 4.53 kB/s (<0.01%), Out: 2.92 kB/s (<0.01%)
    Interface Intel[R] Ethernet 25G 2P E810-XXV OCP 2 [5], (up), MAC: B4:83:51:0B:99:B0, Speed: 25 GBit/s, In: 257 B/s (<0.01%), Out: 664 B/s (<0.01%)
    Memory and pagefile RAM: 42.91% - 110 GiB of 255 GiB, Virtual memory: 42.54% - 125 GiB of 293 GiB
    Processor Queue 15 min load: 0.03, 15 min load per core: 0.00 (144 logical cores)
    Service Summary Autostart services: 78, Stopped services: 4
    System Time Offset: -556 milliseconds
    Uptime Up since 2025-12-22 16:42:45, Uptime: 79 days 3 hours
    No piggyback files for ‘app-klm’. Skip processing.
    No piggyback files for ‘app-klm.int.osram-light.com’. Skip processing.
    [cpu_tracking] Stop [7f886b326a20 - Snapshot(process=posix.times_result(user=0.3599999999999999, system=0.0, children_user=0.0, children_system=0.0, elapsed=0.3999999985098839))]
    [agent] Success, [piggyback] Success (but no data found for this host), execution time 1.6 sec | execution_time=1.610 user_time=0.390 system_time=0.010 children_user_time=0.000 children_system_time=0.000 cmk_time_agent=1.170
    OMD[sitename2]:~$

Output of the debug command shows the total no. of processes as 144 but it is different is GUI for both the servers.
Need to find out if this is a checkmk issue or if there is some valid reason for this discrepancy.

Kindly assist. Thanks in advance!!

2

Hey @NishV,

this is a known Windows limitation affecting any system with more than
64 logical processors — not a Checkmk bug.

Root cause: Windows Processor Groups

Windows uses a 64-bit affinity bitmask to represent logical processors.
For systems exceeding 64 logical processors, it splits them into
Processor Groups of up to 64 each. Your 144-processor systems get
two groups (e.g. 72 + 72).

The winperf_processor check uses the legacy \Processor performance
counter, which is not processor-group-aware and only sees one group at
a time — hence the reported 64 or 16 instead of 144.

Microsoft documents this explicitly:

The two servers show different values (64 vs. 16) because Windows
assigns processes to groups in round-robin, so depending on which group
the Checkmk agent process landed in at startup, it sees a different
subset of processors.

Microsoft also documents this specific symptom:

The actual CPU utilization percentage is still correct — it’s
averaged across what the agent can see — but the core count in the
service output will be wrong on these systems.

The correct total (144) is visible in the Processor Queue service,
which uses Win32_ComputerSystem.NumberOfLogicalProcessors and is
group-aware.

Greetz Bernd

3

Yes, it’s not a bug, Checkmk simply uses an unsuitable counter that delivers incorrect values in this context. As Checkmk likes to say: if it’s not a bug, then it’s a feature request. :wink:

@ NishV
You should still open a ticket with Checkmk — maybe you’ll get lucky and they’ll fix it.

4

Hi @NishV !

It does seem like something that should be fixed. If you have a support contract, please consider creating a ticket with all the information, so my colleagues could take care of it.
If you do not have a support contract, please let me know.

1 Like
6

Thank you all for the response!

1 Like