RES: [Nagiosplug-help] NSClient fix needed

[Sandro Vaz]

Tim:

After some tests here in my W2K in Portuguese, i found the same 99% result
at \\Processor(_Total)\\% Processor Time counter. And for other counters, i
have only zeroes after the decimal comma. I have tried 1.7.0.0 and 1.6.0.2
versions, besides the current one.

In some W2K hosts, English version, I´ve got 100% at \\Processor(_Total)\\%
Processor Time, and strange info when querying \\Process(some_process\\%
Processor Time). Well, let´s go on living with it...

Just a question: if you don´t have Delphi, how did you compile the code with
the changes? If you have some working NSCLient executable, PLMK.

TIA,

Sandro Vaz

-----Mensagem original-----
De: nagiosplug-help-admin at lists.sourceforge.net
[mailto:nagiosplug-help-admin at lists.sourceforge.net] Em nome de Tim
Shouldice
Enviada em: sábado, 29 de março de 2003 02:52
Para: nagiosplug-help at lists.sourceforge.net
Assunto: [Nagiosplug-help] NSClient fix needed


I often been perplexed by the results returned by the NSClient for some of
the counters. Some, like \\Processor(_Total)\\% Processor Time were
returning 99 all the time, others returned 0 all the time, others returned
data that was not consistent with the output from the Perfmon tools (same
trends, different values, same host). While others worked perfectly fine!
Additionally, the internal code called the same counter and seemed to be
getting results.

After a review of the source code and review of Microsoft's documentation on
the PDH api, it seems that some of the counters require two samples to
report correct data. There are two separate functions -
PdhGetRawCounterValue (which is raw, unformatted and uncalculated) and the
more useful PdhGetFormattedCounterValue (which calculates formatted value
and somtimes needs two data points to do it - eg. functions with percentages
of usage and rates per second). The source code within NSClient uses
PdhGetFormattedCounterValue as follows:

uNSClient.pas
// Collect the data
PdhCheck('Collect ' + sCounter, PdhCollectQueryData(qryPDHQuery));
// Process Custom counter
PdhCheck(sCounter, PdhGetFormattedCounterValue(custom_counter,
PDH_FMT_DOUBLE, nil, CounterValue));
...
However, in both the documentation, and in samples on MSDN, it is clear that
two calls to PdhCollectQueryData with a sleep between are required. Here is
an excerpt from Microsoft's sample code (in c):
// "Prime" counters that need two values to display a 
//   formatted value.
pdhStatus = PdhCollectQueryData (hQuery);

// Wait one interval.
Sleep(SAMPLE_INTERVAL_MS);

// Get the current data values.
pdhStatus = PdhCollectQueryData (hQuery);
SAMPLE_INTERVAL_MS was a constant defined as 1000.
I compiled and tested the samples and found when I used the query, wait,
query method that my counters returned correctly, however if I commeneted
out the 'prime counter' query and the sleep, then the results were the same
funny ones I get with NSClient.
It seems the following two lines need to be added to NSClient
>PdhCheck('Collect ' + sCounter, PdhCollectQueryData(qryPDHQuery));
sleep(1000);
PdhCheck('Collect ' + sCounter, PdhCollectQueryData(qryPDHQuery));
>// Process Custom counter
>PdhCheck(sCounter, PdhGetFormattedCounterValue(custom_counter,
PDH_FMT_DOUBLE, nil, CounterValue));
I do not have access to a Dephi environment to add these lines and
recompile, is there anyone who can and then post the updated executable?
Additionally, it is not well documented but a review of the source code
demonstrates that the counters.defs file is purely used for some of internal
data collection for commands other than COUNTER, adding additional counters
to this file is not required and they would not even be used. The file is
used to compensate for the good folks at Microsoft changing the CPU usage
counter between NT and Win2k and to enable the application to work with
different language versions of the OS. The custom counter function does not
use this file or the language definitions because it is the counter name
itself that changes between language versions of the OS. Early programs that
gathered counter information directly from the registry needed the language
version because the counter values are stored under a registry key linked to
the language. This not apply when using the PDH libraries.
Cheers,
Tim Shouldice


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