Network Monitor Multi-Threading

The ActiveXperts Network Monitor Engine (a Windows Service) is responsible for monitoring servers, workstations and devices from a central point. It is designed to run multiple checks simultaneously. To do so, it uses so called 'threads'. Multi-threading gives a program the ability to perform several tasks concurrently.

In ActiveXperts Network Monitor, multiple threads are spawned, including:

Dispatcher - holds the configuration of the software. It has a queue of rules and decides which rules need to be checked. It determines which threads are busy and which threads are not, and passes a rule to a thread that is capable of handling that type of rule;
Notifications and Reports - Notifications can be time consuming, and are therefore assigned to threads to do its job. For instance, an SMS message through an SMSC dial-up provider can take up to 90 seconds. A NetPopup notification message to a non-existing NetBIOS recipient can take up to 10 seconds;
Checks - There are many threads for different checks, to optimize ActiveXperts Network Monitor's monitoring performance. There are threads for ICMP checks, Oracle checks, etc.

The number of threads strongly influences the performance of the ActiveXperts Network Monitor Engine (service). If there are only a few threads, the software will not use much CPU and memory resources, but the throughput of checks may be low. By increasing the number of threads, the throughput will increase. However, too many threads will consume too many system resources together (each thread consumes memory and CPU), decreasing the performance of the Network Monitoring engine dramatically.

It is recommended to have less than 40 threads on an average server. If - for instance - you have a lot of ICMP checks, and only a few VBScript based checks, you can increase performance by configuring a few more ICMP threads and a few less VBScript threads.

On more powerful servers, you can configure more threads.

Configuring the number of Threads

To configure the number of threads, choose Options from the Tools Menu and select the Advanced tab. Press on the top-most button.

You find all different types of threads. You can change the number of threads that is spawned when the ActiveXperts Network Monitor is started. As a result, changes take affect after you restart the service!

The following threads are used by the network Monitor Engine (service):

ICMP/Ping - Responsible for handling 'ICMP/Ping' checks. Default number of ICMP/Ping threads: 4;
Win32 - Responsible for handling the following checks: 'Directory Size', 'Disk Space', 'Service' and 'File Existence'. Default number of Win32 threads: 4;
WMI - Responsible for handling all WMI based checks: 'CPU', 'Disk Drives', 'Memory', 'Printer', 'Process' and 'Event Log'. Default number of WMI threads: 4;
HTTP - Responsible for handling HTTP/HTTPs checks. Default number of HTTP threads: 4;
VBScript - Responsible for handling VBScript based checks, including custom VBScript checks. Default number of VBScript threads: 4.
IMPORTANT: you cannot define more than 8 VBScript threads;
Oracle - Responsible for handling Oracle checks. Default number of Oracle threads: 1.
IMPORTANT: you can configure only 1 Oracle thread;
OLE/DB - Responsible for checking OLE/DB compliant databases, including MS Access and MS SQL. Default number of OLE/DB threads: 2;
Socket - Responsible for Winsock related checks: 'TCP', 'POP3', 'SMTP', 'FTP', 'RSH', 'SNMP', 'NTP', 'NNTP', 'Terminal Server', 'IMAP' and 'DNS'. Default number of Socket threads: 4;
Environmental - Responsible for Environmental related checks: 'Temperature', 'Humidity' and 'Wetness'. Default number of Environental threads: 2.