You can perform the following types of CPU binding on Windows:

The following sections describe these features.

On a multiple‑CPU machine running the Windows operating system, the operating system assigns an ID number to each processor. Windows Task Manager lists the IDs of the available processors. The numbering starts at 0.

If you are not licensed to use all the CPU cores on the iHub 3 host machine, you must bind iHub 3 to the appropriate number of CPUs. To bind iHub3 to a set of processors, you modify the acpmdconfig.xml file in AC_SERVER_HOME\etc. For example, to bind processors to four logical cores, add the following line to acpmdconfig.xml:

After restarting iHub, ihubc.log shows this setting in the System Bound field, for example:

The following example shows the settings for a two CPU (0,1) machine running Windows, which uses only one CPU (0) for BIRT iHub:

You can also perform multiple‑core CPU binding, similar to the way you bind to a single CPU, as described in the previous section. To BIRT iHub, each core appears as a logical CPU.

For example, on a dual‑core, two‑CPU system, setting the DaemonCPUaffinity value to 0,1 binds BIRT iHub to both cores on the first CPU. Setting the value to 0,2 binds BIRT iHub to one core on each CPU. Setting the value to 0 binds BIRT iHub to one core on the first CPU.

Actuate does not recommend restricting BIRT iHub processing on a multiple‑core CPU machine to one core for licensing purposes. BIRT iHub System achieves significant performance gains on a multiple-core CPU machine.

For example, BIRT iHub scales nearly perfectly from 1 to 2 cores and gets 50% better throughput on a dual‑core system than on a two‑CPU system.

Some Intel processors use hyperthreading, a technology that counts each physical processor as a specific number of logical processors. The operating system and any programs running on the machine see the number of logical processors, not the number of physical processors.

When a machine uses hyperthreading, Windows Task Manager lists the logical processors, not the physical ones. You specify the number of logical processors in the environment variable. When a machine uses hyperthreading, BIRT iHub calculates the number of bound processors by dividing the number of bound logical processors by the number of logical processors for each physical processor. If the result contains a decimal component, BIRT iHub uses the next highest integer. For example, it rounds 4.3 to 5. In the following example, a machine has four physical processors. With hyperthreading enabled, each physical processor corresponds to two logical processors. The machine has the following logical processors available:

If you bind BIRT iHub to the five logical processors 0, 2, 3, 6, and 7, it calculates the number of bound processors as:

BIRT iHub rounds this number up to determine that you have three bound processors.