System and method for compiling a computer program

A system for compiling a computer program for execution on a data processing apparatus having memory configured into a plurality of memory sections, each memory section having a record of attributes associated therewith identifying one or more access properties associated with that memory section, said access properties comprising at least one of a size of said associated memory section, latency of an access, energy cost of an access, an available access bandwidth to the associated memory section, energy cost of storing a data unit in the associated memory section and an indication as to whether access to the associated memory section is contended due to sharing with other data processing apparatuses, the system comprising:

• compiler logic configured to perform a compilation in order to generate a plurality of code portions each with an initial mapping of the program in the memory;
• cost function logic configured to evaluate a cost function to generate a cost value associated with the initial mapping of the plurality of code portions, said cost function being dependent on said record of attributes of at least one of said plurality of memory sections;
• the compiler logic, if the cost value does not satisfy a threshold cost value, configured to re-perform the compilation of the program into a plurality of code portions having regard to the record of attributes of each memory section in order to generate a modified mapping;
• the cost function logic configured to re-evaluate the cost function to generate a revised cost value associated with the modified mapping by accounting an access cost based on said attributes;
• the compiler logic and cost function logic configured to iteratively repeat the generating of the modified mapping, the re-performing of the compilation and the re-evaluating of the cost function until a predetermined condition is met;
• wherein once the predetermined condition is met the mapping whose associated cost value most closely satisfied the threshold cost value is output, wherein said compiler logic uses a set of operating constraints when generating the modified mapping and re-performing said compilation.

A method of compiling a computer program for execution on a data processing apparatus having memory configured into a plurality of memory sections, each memory section having a record of attributes associated therewith identifying one or more access properties associated with that memory section, said access properties comprising at least one of a size of the associated memory section, latency of an access, energy cost of an access, an available access bandwidth to the associated memory section, energy cost of storing a data unit in the associated memory section and an indication as to whether access to the associated memory section is contended due to sharing with other data processing apparatuses, the method comprising the steps of:

• a) performing a compilation in order to generate a plurality of code portions each with an initial mapping in the memory;
• b) evaluating a cost function to generate a cost value associated with the initial mapping of the plurality of code portions, said cost function being dependent on said record of attributes of at least one of said plurality of memory sections;
• c) if the cost value does not satisfy a threshold cost value, re-performing the compilation of the program into a plurality of code portions having regard to the record of attributes of each memory section in order to generate a modified mapping;
• d) re-evaluating the cost function to generate a revised cost value associated with the modified mapping by accounting an access cost based on said attributes;
• e) iteratively repeating steps (c) and (d) until a predetermined condition is met;
• and
• f) outputting the mapping whose associated cost value most closely satisfied the threshold cost value;
• wherein at least said steps (b) to (d) are performed by a driver tool which receives at least the cost function and the record of each memory section as inputs and produces the modified mapping as an output.

A system for compiling a computer program for execution on a data processing apparatus having memory configured into a plurality of memory sections, each memory section having a record of attributes associated therewith identifying one or more access properties associated with that memory section, said access properties comprising at least one of a size of said associated memory section, latency of an access, energy cost of an access, an available access bandwidth to the associated memory section, energy cost of storing a data unit in the associated memory section and an indication as to whether access to the associated memory section is contended due to sharing with other data processing apparatuses, the system comprising:

• compiler logic configured to perform a compilation in order to generate a plurality of code portions each with an initial mapping of the program in the memory;
• a driver tool configured to evaluate a cost function to generate a cost value associated with the initial mapping of the plurality of code portions, said cost function being dependent on said record of attributes of at least one of said plurality of memory sections;
• said driver tool, if the cost value does not satisfy a threshold cost value, configured to re-perform the compilation of the program into a plurality of code portions having regard to the record of attributes of each memory section in order to generate a modified mapping;
• said driver tool configured to re-evaluate the cost function to generate a revised cost value associated with the modified mapping by accounting an access cost identified by said attributes;
• said driver tool and cost function logic configured to iteratively repeat the generating of the modified mapping, re-performing of the compilation and the re-evaluating of the cost function until a predetermined condition is met;
• wherein once the predetermined condition is met the mapping whose associated cost value most closely satisfied the threshold cost value is output;
• and
• wherein said driver tool receives at least the cost function and the record of each memory section as inputs and produces the modified mapping as an output.

A method of compiling a computer program for execution on a data processing apparatus having memory configured into a plurality of memory sections, each memory section having a record of attributes associated therewith identifying one or more access properties associated with that memory section, said access properties comprising at least one of a size of the associated memory section, latency of an access, energy cost of an access, an available access bandwidth to the associated memory section, energy cost of storing a data unit in the associated memory section and an indication as to whether access to the associated memory section is contended due to sharing with other data processing apparatuses, the method comprising the steps of:

• a) performing a compilation in order to generate a plurality of code portions each with an initial mapping in the memory;
• b) evaluating a cost function to generate a cost value associated with the initial mapping of the plurality of code portions, said cost function being dependent on said record of attributes of at least one of said plurality of memory sections;
• c) if the cost value does not satisfy a threshold cost value, re-performing the compilation of the program into a plurality of code portions having regard to the record of attributes of each memory section in order to generate a modified mapping;
• d) re-evaluating the cost function to generate a revised cost value associated with the modified mapping by accounting an access cost based on said attributes;
• e) iteratively repeating steps (c) and (d) until a predetermined condition is met;
• and
• f) outputting the mapping whose associated cost value most closely satisfied the threshold cost value, wherein when evaluating the cost function at least one of the following factors associated with a memory access is derived from the access properties identified in the associated record:
• power consumption associated with the memory that is the subject of the memory access;
• latency of the memory that is the subject of the memory access;
• bandwidth associated with the memory that is the subject of the memory access;
• cost of the memory that is the subject of the memory access;
• and
• potential impact on other elements of the data processing apparatus with which the memory that is the subject of the memory access is shared.

A system for compiling a computer program for execution on a data processing apparatus having memory configured into a plurality of memory sections, each memory section having a record of attributes associated therewith identifying one or more access properties associated with that memory section, said access properties comprising at least one of a size of said associated memory section, latency of an access, energy cost of an access, an available access bandwidth to the associated memory section, energy cost of storing a data unit in the associated memory section and an indication as to whether access to the associated memory section is contended due to sharing with other data processing apparatuses, the system comprising:

• compiler logic configured to perform a compilation in order to generate a plurality of code portions each with an initial mapping of the program in the memory;
• cost function logic configured to evaluate a cost function to generate a cost value associated with the initial mapping of the plurality of code portions, said cost function being dependent on said record of attributes of at least one of said plurality of memory sections;
• the compiler logic, if the cost value does not satisfy a threshold cost value, configured to re-perform the compilation of the program into a plurality of code portions having regard to the record of attributes of each memory section in order to generate a modified mapping;
• the cost function logic configured to re-evaluate the cost function to generate a revised cost value associated with the modified mapping by accounting an access cost based on said attributes;
• the compiler logic and cost function logic are configured to iteratively repeat the generating of the modified mapping, re-performing of the compilation and the re-evaluating of the cost function until a predetermined condition is met, wherein once the predetermined condition is met the mapping whose associated cost value most closely satisfied the threshold cost value is output;
• and
• when evaluating the cost function, at least one of the following factors associated with a memory access is derived from the access properties identified in the associated record:
• power consumption associated with the memory that is the subject of the memory access;
• latency of the memory that is the subject of the memory access;
• bandwidth associated with the memory that is the subject of the memory access;
• cost of the memory that is the subject of the memory access;
• and
• potential impact on other elements of the data processing apparatus with which the memory that is the subject of the memory access is shared.