Apple Inc.

P.a. Semi, Inc.

Shih-Chieh Wen

Ramesh B Gunna

Wei-Han Lien

Jong-Suk Lee

Richard F Russo

Christopher M Tsay

Lior Zimet

Mridul Agarwal

Gideon N Levinsky

Tal Kuzi

Charles E Tucker

Jeffrey E Gonion

Richard H Larson

Tse-Yu Yeh

Brian P Lilly

Ian D Kountanis

John H Mylius

Bernard Joseph Semeria

David James Williamson

Brett Stanley Feero

Peter J Bannon

Andrew J Beaumont-Smith

Conrado Blasco

Jaidev Prasad Patwardhan

Joshua P De Cesare

Gerard Richard Williams

Sandeep Kumar Gupta

Edgardo F Klass

Toshinari Takayanagi

James Nolan Hardage

Pradeep Kanapathipillai

Rohit Kumar

John H Kelm

Honkai Tam

Jason M Kassoff

Srikanth Balasubramanian

Daniel U Becker

Suresh B Periyacheri

Rajat Goel

Andrew J Demas

Preethi Bhargavi Sama

An interrupt delivery mechanism for a system includes and interrupt controller and a plurality of cluster interrupt controllers coupled to respective pluralities of processors in an embodiment. The interrupt controller may serially transmit an interrupt request to respective cluster interrupt controllers, which may acknowledge (Ack) or non-acknowledge (Nack) the interrupt based on attempting to deliver the interrupt to processors to which the cluster interrupt controller is coupled. In a soft iteration, the cluster interrupt controller may attempt to deliver the interrupt to processors that are powered on, without attempting to power on processors that are powered off. If the soft iteration does not result in an Ack response from one of the plurality of cluster interrupt controllers, a hard iteration may be performed in which the powered-off processors may be powered on.

Scalable interrupts

Some aspects of this disclosure relate to a peak power manager that includes a first power estimate accumulator circuit configured to receive one or more power estimates associated with one or more subsystems and to generate a first accumulated power estimate. The peak power manage can further include a first-in first-out (FIFO) storage circuit configured to store a plurality of first accumulated power estimates associated with a plurality of clock cycles corresponding to a moving time interval window. The peak power manager can further include a second power estimate accumulator circuit configured to accumulate the plurality of first accumulated power estimates to generate a second accumulated power estimate and a control circuit. The control circuit can be configured to compare the second accumulated power estimate with a threshold power and generate a control signal to control one or more events at the one or more subsystems in response to the second accumulated power estimate satisfying a condition associated with the threshold power.

Peak power management for processing units

In an embodiment, an apparatus includes a plurality of memories configured to store respective data in a plurality of branch prediction entries. Each branch prediction entry corresponds to at least one of a plurality of branch instructions. The apparatus also includes a control circuit configured to store first data associated with a first branch instruction into a corresponding branch prediction entry in at least one memory of the plurality of memories. The control circuit is further configured to select a first memory of the plurality of memories, to disconnect the first memory from a power supply in response to a detection of a first power mode signal, and to cease storing data in the plurality of memories in response to the detection of the first power mode signal.

Methods for partially preserving a branch predictor state

Systems, apparatuses, and methods for retaining architected state for relatively frequent switching between sleep and active operating states are described. A processor receives an indication to transition from an active state to a sleep state. The processor stores a copy of a first subset of the architected state information in on-die storage elements capable of retaining storage after power is turned off. The processor supports programmable input/output (PIO) access of particular stored information during the sleep state. When a wakeup event is detected, circuitry within the processor is powered up again. A boot sequence and recovery of architected state from off-chip memory are not performed. Rather than fetch from a memory location pointed to by a reset base address register, the processor instead fetches an instruction from a memory location pointed to by a restored program counter of the retained subset of the architected state information.

Architected state retention for a frequent operating state switching processor

In an embodiment, processors may have associated special purpose registers (SPRs) such as model specific registers (MSRs), used to communicate IPIs between the processors. In an embodiment, several types of IPIs may be defined, such as one or more of an immediate type, a deferred type, a retract type, and/or a non-waking type. The immediate IPI may be delivered and may cause the target processor to interrupt in response to receipt of the IPI. The deferred IPI may be delivered within a defined time limit, and not necessarily on receipt by the target processor. The retract IPI may cause a previously transmitted IPI to be cancelled (if it has not already caused the target processor to interrupt). A non-waking IPI may not cause the target processor to wake if it is asleep, but may be delivered when the target processor is awakened for another reason.

Intracluster and intercluster interprocessor interrupts including a retract interrupt that causes a previous interrupt to be canceled

A method and apparatus for reducing capacitor noise in electronic systems is disclosed. A system includes at least one functional circuit block coupled to receive a variable supply voltage. The value of the supply voltage is controlled by a power management circuit. Changing a performance state of the functional circuit block includes increasing the supply voltage for higher performance, and reducing the supply voltage for reduced performance demands. The power management circuit, in changing to a higher performance state, increases the supply voltage at a first rate. A rate control circuit causes the power management circuit to reduce the supply voltage, when changing to a lower performance state, at a second rate that is less than the first rate.

Method and apparatus for reducing capacitor-induced noise

An IC in which a power state of a circuit in one power domain is managed based at least in part on a power state of a circuit in another power domain is disclosed. In one embodiment, an IC includes first and second functional circuit blocks in first and second power domains, respectively. A third functional block shared by the first and second is also implemented in the first power domain. A power management unit may control power states of each of the first, second, and third functional circuit blocks. The power management circuit may, when the first functional circuit block is in a sleep state, set a power state of the third functional block in accordance with that of the second functional circuit block.

Managing power state in one power domain based on power states in another power domain

Systems, apparatuses, and methods for reaching power targets across different clock domains are described. In various embodiments, a first processor complex and a second processor complex operate while powered by a same, single power plane, but with respective clock domains. When a request is detected to change an operating mode of a particular core from one of the processor complexes to an operating mode which does not provide the worst-case power supply load on the single power plane, an amount of voltage margin to recover from the operational voltage is determined based on the second operating mode prior to granting the request and based on each other core in the complexes operating in respective current operating modes. An operational voltage less the determined voltage margin to recover is assigned to the processor complexes while different clock frequencies are assigned to the processor complexes.

Single power plane dynamic voltage margin recovery for multiple clock domains

Methods for partially saving a branch predictor state

In an embodiment, an integrated circuit may include one or more processors. Each processor may include multiple processor cores, and each core has a different design/implementation and performance level. The processor may support multiple processor states (PStates). Each PState may specify an operating point (e.g. a combination of supply voltage magnitude and clock frequency), and each PState may be mapped to one of the processor cores. During operation, one of the cores is active: the core to which the current PState is mapped. If a new PState is selected and is mapped to a different core, the processor may automatically context switch the processor state to the newly-selected core and may begin execution on that core. The context switch may be performed using a special purpose register (SPR) interconnect. Each processor core in a given processor may be coupled to the SPR interconnect to permit access to the external SPRs.

Hardware migration between dissimilar cores

A system and a method which include one or more processors, a memory coupled to at least one of the processors, a communication link coupled to the memory, and a power management unit. The power management unit may be configured to detect an inactive state of at least one of the processors. The power management unit may be configured to disable the communication link at a time after the processor enters the inactive state, and disable the memory at another time after the processor enters the inactive state.

L2 flush and memory fabric teardown

A system for managing a change in a frequency of a clock signal, including a clock generator configured to output the clock signal, a clock divider coupled to the output of the clock generator, a processor configured to select the frequency of the clock signal, and a clock management circuit. The clock management circuit may be configured to set the clock generator to adjust the clock signal to the selected frequency. The clock management circuit may be further configured to adjust a divisor value of the clock divider in a plurality of steps in response to a determination the clock signal stabilized at the selected frequency. A new divisor value may be selected during each step in the plurality of steps and each step may occur after a given time period.

Method to manage current during clock frequency changes

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San Jose, CA, United States of America

Shih-Chieh Wen