Configuring How Many Engines Run

There are three settings in the Engine configuration that determine how many Engine instances an Engine Daemon can run.

The SMP Enabled property specifies if the Engine configuration starts an Engine instance per processor core on the machine. This is set to True by default. Specifically, when SMP is enabled, the Engine Daemon runs a number of Engine Instances equal to the value of the Minimum Engine Instances property or the number of processor cores on the machine, whichever is higher. By default, this is set to 1, meaning the number of Engine instances is always the number of cores.

If SMP is disabled, the Engine Daemon always runs the number of Engine instances set in the Minimum Engine Instances property in the Engine configuration.

You can also adjust the number of Engine instances used, to reserve a certain number of cores for non-Engine activity. The value of the Core Relative Engine Instances parameter is added to the value specified in Minimum Engine Instances. The relative value can be a positive or negative number.

For example, if you want to ensure that a single core is always available with no Engine running on it, set the value of Core Relative Engine Instances to -1. If a 4-core machine uses this Engine configuration, its number of Engine instances is the higher of its number of cores and the minimum instances (4) plus the relative instances value (-1), or 3. If a 2-core machine uses this Engine configuration, it starts one Engine instance, leaving the other core free.

You can also manually specify the number of instances that can run for an Engine Daemon. If you go to the Grid Components > Engines > Daemon Admin page, there is a list in the Instances column that enables you to select Default or auto SMP. You can type a number into this control to override the number of instances that can run.