Patent Grant
9996135
Embodiments relate to power management of a system, and more particularly to operating voltage control in a processor.
Advances in semiconductor processing and logic design have permitted an increase in the amount of logic that may be present on integrated circuit devices. As a result, computer system configurations have evolved from a single or multiple integrated circuits in a system to multiple hardware threads, multiple cores, multiple devices, and/or complete systems on individual integrated circuits. Additionally, as the density of integrated circuits has grown, the power requirements for computing systems (from embedded systems to servers) have also escalated. Furthermore, software inefficiencies, and its requirements of hardware, have also caused an increase in computing device energy consumption. In fact, some studies indicate that computing devices consume a sizeable percentage of the entire electricity supply for a country, such as the United States of America. As a result, there is a vital need for energy efficiency and conservation associated with integrated circuits. These needs will increase as servers, desktop computers, notebooks, Ultrabooks™, tablets, mobile phones, processors, embedded systems, etc. become even more prevalent (from inclusion in the typical computer, automobiles, and televisions to biotechnology).
Dynamic loadline handling optimizes operational voltages by dynamically adjusting an operating voltage based on the worst case current draw for a particular configuration. From a transition ordering perspective, a voltage increase is required for a core or other processor logic to exit a low power state, because an extra core being awake means higher worst case current (even though the voltage required at the gate has not increased). The result of this requirement is that low power state exits cannot proceed ahead of voltage increases from an ordering perspective. However, in certain situations, such as where a large voltage increase is under way, the low power state exit be undesirably delayed.
In various embodiments, voltage transitions within a processor may be segmented into two or more segments. In an embodiment, a dispatcher or other control logic of the processor may controllably cause such multi-phase voltage ramps. In operation, a first segment is a transition to an interim or safe voltage level, which is at a sufficient voltage level to cover all active agents (and at least one additional agent) running at a lower frequency in a particular transition. Any additional voltage increase to enable a pending frequency increase requested for one or more of the agents is handled in a second segment of the transition, which can occur after a low power state exit of the additional agent. Using such an embodiment, the worst case voltage ramp incurred before a low power state exit may be a worst case load line adder (e.g., 50 millivolts (mV)), rather than a full scale voltage range (e.g., from a minimum operating voltage to a maximum operating voltage, which for example may be 400 mV). In this way, a reduced latency for allowing an agent to exit a low power state may be realized.
Referring now to
As seen, processor 110 may be a single die processor socket including multiple core units 120a-120n. In an embodiment, each core unit may include multiple cores, a cache memory, an interface unit and so forth. In addition, each core may be associated with an individual low dropout regulator (LDO) 125a-125n to allow for fine-grained control of voltage and thus power and performance of each individual core unit. In an embodiment, the LDOs may be controlled in a first mode to be engaged to further regulate voltages provided to a core, or in a second mode to be bypassed such that the received external voltage is bypassed without further regulation. As such, each core can operate at an independent voltage and frequency, enabling great flexibility and affording wide opportunities for balancing power consumption with performance.
Still referring to
Also shown is a power control unit (PCU) 138, which may include hardware, software and/or firmware to perform power management operations with regard to processor 110. In various embodiments, PCU 138 may include logic to perform multiple sequencing operations to update an operating voltage to enable faster agent wakeups in accordance with an embodiment of the present invention. Furthermore, PCU 138 may be coupled via a dedicated interface to external voltage regulator 160. In this way, PCU 138 can instruct the voltage regulator to provide a requested regulated voltage to the processor. While not shown for ease of illustration, understand that additional components may be present within processor 110 such as additional uncore logic and other components such as internal memories, e.g., one or more levels of a cache memory hierarchy and so forth.
Although the following embodiments are described with reference to energy conservation and energy efficiency in specific integrated circuits, such as in computing platforms or processors, other embodiments are applicable to other types of integrated circuits and logic devices. Similar techniques and teachings of embodiments described herein may be applied to other types of circuits or semiconductor devices that may also benefit from better energy efficiency and energy conservation. For example, the disclosed embodiments are not limited to any particular type of computer systems, and may be also used in other devices, such as handheld devices, systems on chip (SoCs), and embedded applications. Some examples of handheld devices include cellular phones, Internet protocol devices, digital cameras, personal digital assistants (PDAs), and handheld PCs. Embedded applications typically include a microcontroller, a digital signal processor (DSP), network computers (NetPC), set-top boxes, network hubs, wide area network (WAN) switches, or any other system that can perform the functions and operations taught below. Moreover, the apparatus′, methods, and systems described herein are not limited to physical computing devices, but may also relate to software optimizations for energy conservation and efficiency. As will become readily apparent in the description below, the embodiments of methods, apparatus′, and systems described herein (whether in reference to hardware, firmware, software, or a combination thereof) are vital to a ‘green technology’ future, such as for power conservation and energy efficiency in products that encompass a large portion of the US economy.
Note that the voltage control described herein may be independent of and complementary to an operating system (OS)-based mechanism, such as the Advanced Configuration and Platform Interface (ACPI) standard (e.g., Rev. 3.0b, published Oct. 10, 2006). According to ACPI, a processor can operate at various performance states or levels, namely from P0 to PN. In general, the P1 performance state may correspond to the highest guaranteed performance state that can be requested by an OS. In addition to this P1 state, the OS can further request a higher performance state, namely a P0 state. This P0 state may thus be an opportunistic or turbo mode state in which, when power and/or thermal budget is available, processor hardware can configure the processor or at least portions thereof to operate at a higher than guaranteed frequency. In many implementations a processor can include multiple so-called bin frequencies above a guaranteed maximum frequency, also referred to as a P1 frequency, exceeding to a maximum peak frequency of the particular processor, as fused or otherwise written into the processor during manufacture. In addition, according to ACPI, a processor can operate at various power states or levels. With regard to power states, ACPI specifies different activity or power consumption states, generally referred to as C-states, C0, C1 to Cn states. When a core is active, it runs at a C0 state, and when the core is idle it may be placed in a core low power state, also called a core non-zero C-state (e.g., C1-C6 states), with each C-state being at a lower power consumption level (such that C6 is a deeper low power state than C1, and so forth).
Referring now to
As further seen in
To further enable power management operations to take effect, microcontroller 210 is coupled to one or more hardware finite state machines (FSMs) 230. Although the scope of the present invention is not limited in this regard in an embodiment multiple such FSMs may be present, each of which is configured to handle various operations. In connection with execution of the FSMs, a set of registers 240 is coupled to the FSMs. One example FSM shown in
In embodiments described herein, dispatcher 235 may be configured as a pre-emptible state machine. That is, the state machine may be configured such that while underlying operations are underway within the processor responsive to dispatched instructions from the state machine (as the state machine traverses from a first state to a second state), one or more new instructions may be received from microcontroller 210 that cause a different flow of operation of the state machine. This may lead to a set of one or more transitions that occur within the state machine without the previous transition being completed. For example, on receipt of a new instruction, the state machine may begin again from its initial state. By using a pre-emptible state machine as described herein, embodiments may enable wakeup operations such as a wakeup of a core or other IP logic block in a low power state to occur with lower latency.
Still referring to
Referring now to
In a particular embodiment, this frequency increase request may be received within a microcontroller of the PCU that executes power control firmware. Still referring to
Note however in the embodiment of
Still referring to
As described above, embodiments provide for a pre-emptible state machine. As such, during execution of this voltage ramp, it can be determined whether a wakeup request is received (diamond 350). In an embodiment, this determination may be made by the microcontroller, which may receive an incoming wakeup request, e.g., from an OS to cause a second IP block, e.g., a second core, to exit a low power state and enter into an active state. If such a request is received during this time period after the successful acknowledgement of reaching the safe voltage level, at block 360 this wakeup of the IP block may be enabled without delay. Stated another way, because the dispatcher requested a two-step increase in voltage, first to a safe voltage level and then to a higher voltage level, the dispatcher can confirm that the processor is receiving at least the safe operating voltage. As such, the dispatcher can cause the IP block to be awoken into an active state without delay. Still referring to
Still with reference to
Referring now to
In a particular embodiment, this frequency decrease request may be received within a microcontroller of the PCU that executes power control firmware. Still referring to
Still referring to
As described above, embodiments provide for a pre-emptible state machine. As such, during execution of this voltage ramp, it can be determined whether a wakeup request is received (diamond 430). In an embodiment, this determination may be made by the microcontroller, which may receive an incoming wakeup request, e.g., from an OS to cause a second IP block, e.g., a second core, to exit a low power state and enter into an active state.
If no wakeup request is received during the down ramp to the safe operating voltage (as determined at diamond 430), control passes next to diamond 460 where it can be determined whether an acknowledgement of the decrease to the safe voltage level has been received. Otherwise control passes back to diamond 430. If the acknowledgement is received, the dispatcher may initiate a decrease to a first, lower voltage (e.g., sufficient to power a single core at a lower frequency) at block 470. In an embodiment, this initiation may be responsive to an instruction from the dispatcher to the voltage regulator module to thus decrease the operating voltage to an appropriate level to allow single core operation at a lower frequency. Thus as illustrated in
Still with reference to
If instead at diamond 430 it is determined that a request is received during this time period after the request to lower the operating voltage to a safe voltage level, at block 440 this wakeup of the IP block may be enabled without delay. Stated another way, because the dispatcher requested a decrease in voltage only to a safe voltage level, the dispatcher can confirm that the processor is receiving at least the safe operating voltage. As such, the dispatcher can cause the IP block to be awoken into an active state without delay.
Still referring to
Still with reference to
While shown in the above several flow diagrams with particular timing sequences and operations to cause an operating voltage of one or more cores of a processor to be increased or decreased, understand that other situations are possible. That is, according to embodiments of the present invention different sequences of incoming requests to a power controller may cause different operations to occur using a multi-level operating voltage ramp control to enable faster guarantee of a safe operating voltage for increasing the number of active cores. Thus although shown with this particular event handling in
Referring now to
However note that instead of making a single request to a voltage regulator to cause a smooth ramp up to this voltage, a request is made to increase the operating voltage to a safe operating voltage, shown at point B, in
Note that after the acknowledgment is received, a second request is issued from the power controller to the voltage regulator to cause the additional ramp up to the higher operating voltage level to enable turbo mode operation. Although not shown for ease of illustration in
Referring now to
However note that instead of making a single request to a voltage regulator to cause a smooth ramp down to this voltage, a request is made to decrease the operating voltage to a safe operating voltage, shown at point D, in
Note that after the acknowledgment of attainment of this safe operating voltage level is received (and assuming no wakeup request has been received), a second request is issued from the power controller to the voltage regulator to cause the additional ramp down to the lower operating voltage level to enable lower frequency mode operation. Although this relatively simplified view is shown in the illustration of
Referring now to Tables 1 and 2, shown are example sequences of operations to perform voltage transitions in accordance with embodiments of the present invention. As seen in these Tables, multiple voltages transition instructions are issued from a dispatcher responsive to requests from a microcontroller to a voltage regulator to guarantee at least a safe operating voltage as described herein. Specifically Table 1 shows operation for an upward transition, and Table 2 shows operation for a downward transition. Each Table shows an input request (to a dispatcher from a microcontroller), an output instruction (to a voltage regulator), and target and status values. Note while shown with particular sequences of operations and specific values, understand the scope of the present invention is not limited in this regard.
In the Tables assume two cores total: low frequency operation is at 1 GHz; high frequency operation is at 3 GHz; at low frequency, headroom for adding a core is +20 mV/core; and headroom for adding a core at high frequency+40 mV/core.
Embodiments can be implemented in processors for various markets including server processors, desktop processors, mobile processors and so forth. Referring now to
In the high level view shown in
In addition to core units, additional processing engines are present within the processor, including at least one graphics unit 520 which may include one or more graphics processing units (GPUs) to perform graphics processing as well as to possibly execute general purpose operations on the graphics processor (so-called GPGPU operation). In addition, at least one image signal processor 525 may be present. Signal processor 525 may be configured to process incoming image data received from one or more capture devices, either internal to the SoC or off-chip.
As seen, all of these various processing units, including core units 510, graphics unit 520 and image signal processor 525 couple to coherent fabric 530. In addition, each of the units may have its power consumption controlled via a power control unit 540. PCU 540 includes a voltage control logic 545 to perform operating voltage transitions according to a multi-level operating voltage ramp profile as described herein. In this way, incoming requests for low power exits can be enabled with little or no latency, as the voltage control logic can guarantee that an incoming rail is at least at a safe operating voltage to enable an additional processing unit to exit a low power state and enter an active state.
As further seen in
Referring now to
In various embodiments, power control unit 655 may include a voltage control logic 659 in accordance with an embodiment of the present invention. As described above, this logic is configured to cause operating voltage changes to occur according to a multi-level ramp profile in order to be able to respond to low power exit requests with reduced latency. In some embodiments, such logic may include one or more state machines that are pre-emptible to allow incoming low power exit requests to be handled during execution of an operating voltage level update.
With further reference to
Referring now to
In general, each core 710 may further include low level caches in addition to various execution units and additional processing elements. In turn, the various cores may be coupled to each other and to a shared cache memory formed of a plurality of units of a last level cache (LLC) 7400-740n. In various embodiments, LLC 740 may be shared amongst the cores and the graphics engine, as well as various media processing circuitry. As seen, a ring interconnect 730 thus couples the cores together, and provides interconnection between the cores, graphics domain 720, signal processor domain 725 and system agent circuitry 750. In one embodiment, interconnect 730 can be part of the core domain. However in other embodiments the ring interconnect can be of its own domain.
As further seen, system agent domain 750 may include display controller 752 which may provide control of and an interface to an associated display. As further seen, system agent domain 750 may include a power control unit 755 which can include a voltage control logic 759 in accordance with an embodiment of the present invention to enable operating voltage updates to occur in a sequenced order to allow for reduced latency low power state exits as described herein. In various embodiments, this logic may be configured as in
As further seen in
Embodiments may be implemented in many different system types. Referring now to
Still referring to
Furthermore, chipset 890 includes an interface 892 to couple chipset 890 with a high performance graphics engine 838, by a P-P interconnect 839. In turn, chipset 890 may be coupled to a first bus 816 via an interface 896. As shown in
The following examples pertain to further embodiments.
In one example, a processor comprises a first domain including a plurality of processing engines, and a power controller including a first logic to receive a first request to increase an operating voltage of a first processing engine of the first domain to a second voltage, to instruct a voltage regulator to increase the operating voltage to an interim voltage, and to thereafter instruct the voltage regulator to increase the operating voltage to the second voltage.
In an example, the power controller includes a microcontroller and a dispatcher engine.
In an example, the dispatcher engine comprises a pre-emptible state machine.
In an example, the first logic comprises the dispatcher engine.
In an example, the dispatcher engine is to receive the first request from the microcontroller responsive to a request for the first processing engine to enter a turbo mode.
In an example, the dispatcher engine is to enable the first processing engine to enter the turbo mode responsive to receipt of an acknowledgement from the voltage regulator that the operating voltage has reached the second voltage.
In an example, the first logic is to receive a first acknowledgement from the voltage regulator that the operating voltage has reached the interim voltage, and to instruct the voltage regulator to increase the operating voltage to the second voltage responsive to the first acknowledgement.
In an example, the first logic is to receive a second request for a second processing engine of the first domain to exit a low power state, and to enable the second processing engine to exit the low power state after receipt of the first acknowledgement.
In an example, the first logic is to receive a third request for the first processing engine to enter a turbo mode, and to instruct the voltage regulator to increase the operating voltage to a third voltage greater than the second voltage.
In an example, the first logic is to enable the first processing engine to enter the turbo mode responsive to a second acknowledgement from the voltage regulator that the operating voltage has reached the third voltage.
In an example, the interim voltage comprises a voltage level sufficient to enable an additional processing engine.
Note that the above processor can be implemented using various means.
In an example, the processor comprises a system on a chip (SoC) incorporated in a user equipment touch-enabled device.
In another example, a machine-readable medium having stored thereon instructions, which if performed by a machine cause the machine to perform a method comprising receiving a frequency increase request for a first intellectual property (IP) logic of a processor, causing an operating voltage provided to the processor by a first voltage regulator to be updated from a first voltage level to an interim voltage level, and after the operating voltage reaches the interim voltage level, enabling a second IP logic of the processor to exit a low power state before enabling the first IP logic to effect the frequency increase.
In an example, the method further comprises receiving a request to wakeup the second IP logic after initiating an update to cause the operating voltage to be updated to a second voltage level, and enabling the second IP logic to wakeup before the operating voltage reaches the second voltage level.
In an example, the method further comprises causing the operating voltage to be updated to a third voltage level greater than the second voltage level.
In an example, the method further comprises after the operating voltage reaches the third voltage level, enabling the first IP logic to enter a turbo mode.
In an example, the method further comprises causing the operating voltage to be updated to the interim voltage level, responsive to a request for the first IP logic to exit the turbo mode, and causing the operating voltage to be updated to the first voltage level, after at least one of the first and second IP logics enters a low power mode.
In another example, a computer readable medium including instructions is to perform the method of any of the above examples.
In another example, an apparatus comprises means for performing the method of any one of the above examples.
In another example, a system comprises a multicore processor including a plurality of cores and a power control unit to cause an operating voltage to be updated, according to a multi-level operating voltage ramp profile, to a second level sufficient to support at least one core at a turbo mode frequency, and a dynamic random access memory (DRAM) coupled to the multicore processor.
In an example, upon completion of a first portion of the multi-level operating voltage ramp profile, the operating voltage is sufficient to support an additional core at a first frequency.
In an example, the power control unit is to allow the additional core to be enabled at the first frequency responsive to an acknowledgement that the first portion of the multi-level operating voltage ramp profile has been completed.
In an example, the power control unit is to initiate a second portion of the multi-level operating voltage ramp profile responsive to the acknowledgement to cause the operating voltage to be updated to the second level.
In an example, the power control unit is to allow the at least one core to enter the turbo mode responsive to a second acknowledgement that the second portion of the multi-level operating voltage ramp profile has been completed.
In an example, the power control unit is to cause the operating voltage to be thereafter reduced from the second level when the at least one core has exited the turbo mode, and to enable the additional core to wakeup before acknowledgement that the operating voltage has reached an interim level.
In another example, a system comprises a display and a memory, and includes the processor of one or more of the above examples.
In another example, a method comprises receiving a frequency increase request for a first intellectual property (IP) logic of a processor, causing an operating voltage provided to the processor by a first voltage regulator to be updated from a first voltage level to an interim voltage level, and after the operating voltage reaches the interim voltage level, enabling a second IP logic of the processor to exit a low power state before enabling the first IP logic to effect the frequency increase.
In an example, the method further comprises receiving a request to wakeup the second IP logic after initiating an update to cause the operating voltage to be updated to a second voltage level, and enabling the second IP logic to wakeup before the operating voltage reaches the second voltage level.
In an example, the method includes causing the operating voltage to be updated to a third voltage level is greater than the second voltage level.
In an example, after the operating voltage reaches the third voltage level, the method enables the first IP logic to enter a turbo mode.
In an example, the method further comprises causing the operating voltage to be updated to the interim voltage level, responsive to a request for the first IP logic to exit the turbo mode, and causing the operating voltage to be updated to the first voltage level, after at least one of the first and second IP logics enters a low power mode.
In an example, a communication device is arranged to perform the method of any one of the above examples.
In an example, at least one machine readable medium comprising a plurality of instructions that in response to being executed on a computing device, cause the computing device to carry out a method according to any one of the above examples.
In another example, a processor comprises a first domain including a plurality of processing engines, and a power controller including a means for receiving a first request to increase an operating voltage of a first processing engine of the first domain to a second voltage, for instructing a voltage regulator to increase the operating voltage to an interim voltage, and thereafter for instructing the voltage regulator to increase the operating voltage to the second voltage.
Understand that various combinations of the above examples are possible.
Embodiments may be used in many different types of systems. For example, in one embodiment a communication device can be arranged to perform the various methods and techniques described herein. Of course, the scope of the present invention is not limited to a communication device, and instead other embodiments can be directed to other types of apparatus for processing instructions, or one or more machine readable media including instructions that in response to being executed on a computing device, cause the device to carry out one or more of the methods and techniques described herein.
Embodiments may be implemented in code and may be stored on a non-transitory storage medium having stored thereon instructions which can be used to program a system to perform the instructions. The storage medium may include, but is not limited to, any type of disk including floppy disks, optical disks, solid state drives (SSDs), compact disk read-only memories (CD-ROMs), compact disk rewritables (CD-RWs), and magneto-optical disks, semiconductor devices such as read-only memories (ROMs), random access memories (RAMs) such as dynamic random access memories (DRAMs), static random access memories (SRAMs), erasable programmable read-only memories (EPROMs), flash memories, electrically erasable programmable read-only memories (EEPROMs), magnetic or optical cards, or any other type of media suitable for storing electronic instructions.
While the present invention has been described with respect to a limited number of embodiments, those skilled in the art will appreciate numerous modifications and variations therefrom. It is intended that the appended claims cover all such modifications and variations as fall within the true spirit and scope of this present invention.
This application is a continuation of U.S. patent application Ser. No. 13/793,037, filed Mar. 11, 2013, the content of which is hereby incorporated by reference.
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| Number | Date | Country | |
|---|---|---|---|
| 20160259389 A1 | Sep 2016 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 13793037 | Mar 2013 | US |
| Child | 15157553 | US |
