Question

This article provides answers to the following questions related to SVM Agent thread scheduling: 

What kind of thread priority does the agent have and how would it play out if the host CPU is busy?

Will the default thread priority interfere with other threads running on the system and is this auto-managed by Windows/MAC/Linux?

Why can't you specify scan thread priority on MAC OSX Systems?

Discussion

All Agents-specifics

SVM Agents will begin background processing mode so that it can perform background work without significantly affecting activity in the foreground. By default, SVM Agents for Windows, Linux, MAC OSX will be installed with lowest thread priority:

THREAD_PRIORITY_IDLE

Windows/Linux-specifics

The thread priority can be changed via the command line using the following optional command-line parameter supported by the Agent for Windows/Linux:

--scan-thread-priority

Windows-specifics

On Windows hosts (SVM Agent for Windows), the configuration of thread priority is more flexible.
You can also configure the default thread priority of your Agents through the Windows registry entry ScanThreadPriority by specifying one of the following available values:  

0: THREAD_PRIORITY_NORMAL

1: THREAD_PRIORITY_BELOW_NORMAL

2: THREAD_PRIORITY_LOWEST

3: THREAD_PRIORITY_IDLE

ScanThreadPriority is setup as aa DWORD registry value in the Windows Registry.  

The agent reads the setting from HKLM\SOFTWARE\Wow6432Node\Secunia\CSI Agent when running under the Local System account, and from HKCU\SOFTWARE\Secunia\CSI Agent when running under a different domain service user account.

See SetThreadPriority Windows API for more details about the parameters of thread priority.
The Software Vulnerability Agent doesn’t use the background processing mode when THREAD_PRIORITY_NORMAL is specified.

MAC OSX-specifics

The scan thread priority for MAC OSX-based SVM Agents cannot be changed due to known performance problems when different than the lowest thread is being used by the SVM Agent on OSX hosts.