Partitioning of memory system resources or performance monitoring

An apparatus comprising:

• processing circuitry to process instructions;
• at least one memory system component to handle memory transactions for accessing data;
• and
• partition identifier storage to store an instruction partition identifier and a data partition identifier;
• wherein when issuing a memory transaction for accessing data, the processing circuitry is configured to issue the memory transaction specifying a partition identifier dependent on the data partition identifier stored in the partition identifier storage;
• when issuing a memory transaction for accessing an instruction, the processing circuitry is configured to issue the memory transaction specifying a partition identifier dependent on the instruction partition identifier stored in the partition identifier storage;
• and
• in response to a memory transaction to be handled, said at least one memory system component is configured to control allocation of resources for handling the memory transaction or manage contention for said resources in dependence on a selected set of memory system component parameters selected in dependence on the partition identifier specified by the memory transaction, or to control, in dependence on said partition identifier, whether performance monitoring data is updated in response to the memory transaction;
• wherein the partition identifier storage is configured to store a performance monitoring partition identifier;
• and
• the processing circuitry is configured to issue the memory transaction specifying a first partition identifier dependent on the data partition identifier when the memory transaction is for accessing data and dependent on the instruction partition identifier when the memory transaction is for accessing an instruction, and a second partition identifier dependent on the performance monitoring partition identifier.

A data processing method comprising:

• processing instructions;
• storing a plurality of instruction partition identifiers and a plurality of data partition identifiers in partition identifier storage;
• issuing a memory transaction to at least one memory system component, the memory transaction specifying a partition identifier dependent on a selected instruction partition identifier when the memory transaction is for accessing an instruction and dependent on a selected data partition identifier when the memory transaction is for accessing data, wherein the selected instruction partition identifier and the selected data partition identifier are selected in dependence on a current operating state in which said instructions are being processed;
• and
• in response to a memory transaction to be handled, said at least one memory system component controlling allocation of resources for handling the memory transaction or managing contention for said resources in dependence on a selected set of memory system component parameters selected in dependence on the partition identifier specified by the memory transaction, or controlling, in dependence on said partition identifier, whether performance monitoring data is updated in response to the memory transaction.