Arm Limited

Ashley John Crawford

Dominic William Brown

Christopher Vincent Severino

Tessil Thomas

James Edward Myers

Andrew Brookfield Swaine

John Michael Horley

Andrew Christopher Rose

Stephan Diestelhorst

Paul Gilbert Meyer

Mark David Werkheiser

Andreas Hansson

Timothy Charles Mace

Carlos Garcia-Tobin

Jose Manuel Silva Dos Santos Marinho

Souvik Chakravarty

David Guillen Fandos

Anouk Martha H Van Laer

There is provided an apparatus comprising a requirement determination unit to determine an energy requirement for a system component. A status determination unit determines status information relating to a plurality of heterogeneous energy stores and actuating system control unit controls an activity of the system component in dependence on the status information relating to the plurality of heterogeneous energy stores and the energy requirement.

Multiple heterogeneous energy stores

A data processing apparatus includes processing circuitry to process an event stream that includes one or more high power events. Tracking circuitry tracks the one or more high power events and power management circuitry manages power consumption by controlling a voltage supply and a frequency of a clock signal provided to the processing circuitry. The power management circuitry controls an extent to which execution by the processing circuitry of the high power events is restricted.

Power management

A data processing apparatus comprises a plurality of processor circuits to process an event stream comprising one or more high energy events. Each of the plurality of processor circuits draws power from a same power rail. Power management circuitry performs power consumption management by controlling a voltage supply to the power rail, and a frequency of a clock signal provided to the plurality of processor circuits. Status analysis circuitry obtains a status of the individual processing load of each of the processor circuits and restriction circuitry performs high energy event restriction on each of the plurality of processor circuits. The power consumption management and the high energy event restriction are both based on the individual processing load of each of the plurality of processor circuits and each of the processor circuits is restrictable by the restriction circuitry independently of others of the processor circuits.

Balancing high energy events

An integrated circuit and method are provided for managing power domains. The integrated circuit has first circuitry provided within a first power domain, and a distributed power controller for controlling transition of the first power domain between a plurality of power states. The distributed power controller comprises at least power control circuitry in a second power domain and additional power control circuitry in a third power domain. Whilst the current power state of the first power domain is in any one of at least two of the plurality of power states, the second power domain is allowed to be placed in a power saving state where the power control circuitry loses knowledge of the current power state of the first power domain. However, the third power domain is prevented from entering that power saving state. Further, the additional power control circuitry is arranged to output a mode status signal that is then used by the power control circuitry, when the second power domain exits the power saving state, to place the power control circuitry into an initial mode of operation that is dependent on the current power state of the first power domain. This ensures that, despite the power control circuitry losing knowledge of the current power state of the first power domain whilst it is in the power saving state, no unintended consequences occur when the second power domain subsequently exits the power saving state.

Technique for managing power domains in an integrated circuit

A data processing apparatus has a number of devices having a normal state and a quiescent state in which the device is ready for being placed in a power saving state. Each device provides at least one preference indication indicative of a preference to operate in the normal state or the quiescent state. A controller controls a common state transition process for transitioning each of the devicesbetween the normal state and the quiescent state based on the preference indication received from each device.

Controlling transitions of devices between normal state and quiescent state

Apparatus comprises master counter circuitry to generate a master count signal in response to a clock signal; slave counter circuitry responsive to the clock signal to generate a respective slave count signal; and a synchronisation connection providing signal communication between the master counter circuitry and the slave counter circuitry; the master counter circuitry being configured to provide to the slave counter circuitry via the synchronisation connection: (i) data indicative of a count offset value and (ii) a timing signal defining a timing relationship between the clock signal and the count offset value; and the slave counter circuitry being configured, during a synchronisation operation for that slave counter circuitry, to initialise a counting operation of that slave counter circuitry in response to the data indicative of the count offset value and a timing signal provided by the master counter circuitry.

Counter circuitry and method

A data processing apparatus () has a number of devices () having a normal state and a quiescent state. Transition sequencing circuitry () controls a sequential state transition process for transitioning each of the devices () in turn between the normal state and the quiescent state. For each device, the transition sequencing circuitry () controls the transition based on at least one preference indication transmitted from that device () providing an indication of a preference to operating the normal state or the quiescent state.

A method, system, and device provide for selective control in a distributed cache system of the power state of a number of receiver partitions arranged in one or more partition groups. A power control element coupled to one or more of the receiver partitions and a coherent interconnect selectively control transition from a current power state to a new power state by each receiver partition of one or more partition groups of the plurality of partition groups.

Segregated power state control in a distributed cache system

Various implementations described herein are directed to a method and apparatus for a low power interface combiner for controlling a cross domain component in a system of two or more power domain controls. The combiner may include a first state for requesting cross domain component quiescence when a first control requests quiescence and a second state for ensuring cross domain component quiescence before accepting the first control quiescence request. The combiner may include a third state for requesting cross domain component quiescence exit when a last control requests quiescence exit and other controls have exited or are exiting quiescence. The combiner may include a fourth state for ensuring cross domain component quiescence exit before accepting the last control quiescence exit request.

Combination of control interfaces for multiple communicating domains

A method of operating a cache and corresponding apparatus are provided. The cache is capable of being only partially powered, and a decision to reduce the proportion of the cache which is currently powered is made based on calculating a memory bandwidth equivalent of expending the current active cache leakage power on memory access. The cache hit bandwidth is compared against this memory bandwidth equivalent and when the cache hit bandwidth is less than the memory bandwidth equivalent, the proportion of the cache which is currently powered is reduced. A analogous decision may also be made and based on calculating a cache hit bandwidth equivalent for an increment increase in cache leakage power, and when the cache miss bandwidth exceeds the cache hit bandwidth equivalent, the proportion of the cache which is currently powered is increased.

Cache power management

There is provided a data processing device including an output port to transmit a request value to an interconnect arranged to implement a coherency protocol, to indicate a request to be subjected to the coherency protocol. An input port receives an acknowledgement value from the interconnect in response to the request value and coherency administration circuitry defines behavior rules for the data processing device in accordance with the coherency protocol and in dependence on the request value and the acknowledgement value. Storage circuitry administers data in accordance with the behavior rules. There is also provided an interconnect including an input port to receive a request value, issued by a data processing device having storage circuitry, to indicate a request for the data processing to be subjected to a coherency protocol. An output port transmits an acknowledgement value to the data processing device in response to the request value and coherency administration circuitry defines behavior rules for the interconnect in accordance with the coherency protocol and in dependence on the request value and the acknowledgement value.

Hardware based coherency between a data processing device and interconnect

An apparatus and a corresponding method of operating the apparatus are disclosed. A component of the apparatus is capable of operating in one of at least two power modes and component power control circuitry which is communicatively coupled to the component causes the component to operate in a selected power mode of those power modes. A system power controller controls operation of the component power control circuitry by setting a power mode lock condition therein. When the power mode lock condition is met the component power control circuitry cannot change the selected power mode of the component. Power control over the component is thus partially delegated from the system power controller to the component power control circuitry.

Delegating component power control

Memory circuitry, a data processing apparatus and a method of storing data are disclosed. The memory circuitry comprises: a memory for storing the data; and control circuitry for controlling power consumption of the memory by controlling a rate of access to the memory such that an average access delay between adjacent accesses is maintained at or above a predetermined value; wherein the control circuitry is configured to determine a priority of an access request to the memory and to maintain the average access delay at or above the predetermined value by delaying at least some accesses from access requests having a lower priority for longer than at least some accesses from access requests having a higher priority.

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Ashdon, United Kingdom

Ashley John Crawford