Patent Application
20110191602
1. Field of the Invention
This invention relates to data processors.
2. Description of the Related Art
Data processors include at least one processor core and are typically implemented on an integrated circuit. Data processors are powered by a power supply (e.g. a voltage regulator) at one or more operating voltages. Typically, higher operating voltages allow for higher operating frequencies.
Because data processors are implemented on integrated circuits, the operating temperature and the operating voltage of the integrated circuit may affect the longevity of the data processor. Typically, the higher the average operating temperature and/or operating voltage, the shorter the longevity (the useful life) of the integrated circuit. Higher operating temperatures and voltages are more likely to generate dielectric breakdown, electro migration, and Negative Bias Temperature Instability.
It is often desirable to operate a data processor at the highest possible operating frequency. However, operating a data processor at relatively high operating frequencies may correspondingly reduce the longevity of a device due to the greater amount of heat generated by the transistors of the device switching at faster speeds and the higher voltage needed to run at the elevated frequencies.
What is needed are improved systems for allowing flexibility of the use of a data processor.
The present invention may be better understood, and its numerous objects, features, and advantages made apparent to those skilled in the art by referencing the accompanying drawings.
The use of the same reference symbols in different drawings indicates identical items unless otherwise noted. The Figures are not necessarily drawn to scale.
The following sets forth a detailed description of a mode for carrying out the invention. The description is intended to be illustrative of the invention and should not be taken to be limiting.
Embodiments described relate to a data processor that is programmable to select a longevity (lifetime) of the device based on parameters such as an indication of operating temperature. Because a higher operating frequency can increase the operating temperature which can reduce the useful life of a data processor, the data processor is programmable to select a particular tradeoff between useful life and increased performance with higher operating frequencies and voltages. Such features may allow a particular model of data processor to be utilized for different applications and/or by different system manufactures. Such a feature may also provide for reduced production costs by reducing the number of models produced by a data processor supplier.
System 100 includes a voltage regulator circuit 105 that receives a voltage identifier value (VID) from processor 103 and generates one or more operating voltages that corresponds to the VID value. Accordingly, processor 103 can control its operating voltage or operating voltages by adjusting the VID value. In some embodiments, the selector may provide multiple VID values, each for controlling the value of a different operating voltage supplied by regulator 105. In an embodiment that provides multiple VIDs, each VID may indicate a specific operating voltage for a particular processor core or a portion of the processor core. In one embodiment, the VID values are digital, but in other embodiment, the VID values are analog. An operating voltage is the voltage supplied by a regulator or other power source to circuitry for powering the circuitry. In one embodiment, components of regulator 105 are not located on the same integrated circuit 101 as processor 103. However in other embodiments, at least some those components of regulator 105 are located on integrated circuit 101.
In the embodiment shown, processor 103 includes a number of processor cores 111, 113, and 115. A processor core includes an execution unit for performing processing operations as per executable code. Each core of processor 103 is of a particular data processing architecture type such as e.g. Power PC, x86, SPARC, MIPS, or an ARM architecture. Each core also is of a particular processor configuration such as e.g. a general purpose processor, a digital signal processor, an applications specific processor, or a network packet inspection processor. In one embodiment, the cores have identical configurations and architectures, but in other embodiments, the cores have different configurations and architectures from each other. For example, one of the cores may be a digital signal processor and the other cores may be general purpose processor of a different architecture.
In the embodiment shown, the maximum operating frequency of at least one core is controlled by the operating voltage, although in other embodiments, the frequency may be independently controlled by a clock circuit 118. Processor 103 includes a system memory 119 that is operably coupled to the cores via a processor bus (not shown). Processor 103 also includes I/O circuitry 117 for coupling to bus 107. Processor 103 includes a clock circuit 118 for providing clock signals to the circuitry of processor 103 including to cores 111, 113, and 115, and memory 119. In one embodiment, each clock signal controls the operating frequency of its respective core. Processor 103 may have other configurations in other embodiments including having other circuits such as e.g. a cache.
Processor 103 includes a system for controlling the operating voltage or voltages by providing a VID indicative of the desired operating voltage or voltages to supply the circuitry of processor 103 including the cores. The operating voltage is limited as a function of a temperature indication to meet a selectable longevity requirement that has been programmed into longevity register 131.
In the embodiment shown, selector 121 includes controller 123 for controlling the operation of selector 121 and a memory 125 for storing sets of VID values that correspond to a set of temperature indication values for each longevity value.
Controller 123 is coupled to temperature sensor 127 for receiving an indication of the junction temperature of processor 103. In one embodiment, sensor 127 includes a thermal monitor (not shown) whose output is proportional to the temperature of the integrated circuit. In the embodiment shown sensor 127 is located in the same integrated circuit 101 as data processor 103. However in other embodiments, sensor 127 may be located off chip. Also in other embodiments, processor 103 includes multiple temperature sensors located throughout processor 103, each providing an indication to controller 123. In one embodiment, each core includes a temperature sensor.
In other embodiments, controller 123 may utilize other values other than a temperature measurement as an indication of the operating temperature. For example, the temperature indication may correspond to a circuit usage value of the circuitry of processor 103. With some systems, the number of cores operating at one time may be indicative of the operating temperature of the processor at that time. Such a value may be generated by the operating system of system 100 and stored in utilization register 132. As the number of devices are turned on or off, the value would change, indicating a higher or lower operating temperature.
Frequency register 129 includes an indication of a desired operating frequency or frequencies for the cores of processor 103. In one embodiment, the desired operating frequency is written to register 129 by the operating system of system 100.
In other embodiments, processor 103 implements a number of performance states. Each performance state includes an associated frequency at which a processor core or cores will operate. The operating frequencies switch with a change in performance states. In one embodiment, the value in frequency register 129 is written by circuitry that reads the performance state and the registers that store the frequency corresponding the performance state. In other embodiments, the controller 123 receives an indication of the performance states and determines the corresponding frequency of the performance state. In one embodiment, the frequencies corresponding the performance states are programmable. In one embodiment, the corresponding frequencies to performance states would be programmed in memory 125 or reflected in the information programmed in memory 125. Controller 123 would then provide a frequency identifier to clock circuit 118 to control an operating frequency provided by the clock circuit.
In one embodiment, the longevity values are programmed by programming one time programmable devices (e.g. fuses, electrically programmable read only memory, or an erasable EPROM that has been configured to be written only once) to store the longevity values. A longevity value is indicative of the desired longevity of the device. Based on the longevity of the device, the selector will provide a VID (and frequency identifier in some embodiments) that will generate or allow an operating frequency that will enable the processor to perform for the desired longevity. In some embodiments, register 131 includes the one time programmable devices. In other embodiments, register 131 is a volatile memory, where the operating system of system 100 reads the values of the one time programmable devices (either on integrated circuit 101 or off chip) and writes those values to register 131 during start up.
In operation, controller 123 receives the longevity value to determine which table of tables 201, 203, and 205 is used to select the VID values. With the appropriate table selected, controller 123 selects the VID value corresponding to the temperature value range as measured by the one or more temperature sensors or as indicated by the configuration indication, and the frequency indication. In an embodiment where each core includes its own temperature sensor, the table selected by the longevity value would be used to select the VID value for the core based on the measured temperature of the sensor associated with the core.
Accordingly, by providing the ability to selectively program a longevity value from a number of possible longevity values, a processor (or core of a processor) can be configured to operate at different operating voltages for a specific temperature or temperature range in order to order to achieve to the desired longevity. For example, if the desired longevity is 3 years, processor 103 can operate at higher operating voltage (and therefore a higher operating frequency) for a given temperature than a processor whose longevity value is longer (e.g. 5 years, 7 years, 9 years, or 15 years). For example, for a temperature of 105 C, a processor may operate at 1.3 volts for a 5 year longevity value versus 1.0 volts for a processor with a longevity value of 8 years. Operating at a higher voltage in some embodiments, allows the processor to operate at a higher frequency.
Memory 125 may store the VID values based on other configurations. For example, memory 125 may includes a number of tables for each desired frequency, where each table includes VID values associated with a particular temperature range and longevity value. In other embodiments, the memory includes a table for each temperature range that includes VID values associated with a particular desired frequency and longevity value. The data in memory 125 may be stored in any number of different ways that are conventional to data storage devices including the use of compression techniques.
The number of temperature values, frequency values, and longevity values may vary with different embodiments. For example, one embodiment may include just two temperature ranges (over 105 C and under 105 C). Also, the frequency values may be for a given frequency range.
In another embodiment, the information shown in
In one embodiment, clock circuit 118 and controller 123 are coupled to change the operating voltage and operating frequency in an ordered manner for processor reliability. In one embodiment for an increase in operating frequency, the operating voltage would first be increased by selector 121 and then clock circuit 118 would increase the operating frequency. Likewise, when decreasing the operating frequency, clock circuit 118 decreases the operating frequency first and then controller 123 lowers the voltage by changing the VID value. In one embodiment, selector 121 controls clock circuit 118, but in other embodiments, clock circuit 118 controls selector 121. In another embodiment, both circuits would be controlled by an other circuit or by the operating system for processor frequency/voltage coordination.
Also in other embodiments, the VID value would be provided internally (e.g. to a register) such that the operating system or other system controlling operating frequency would read the corresponding VID value and alter the operating frequency accordingly.
Still in other embodiments, processor 103 would include a frequency monitoring circuitry (e.g. that includes a ring oscillator circuit) that monitors operating frequency. If the operating frequency is less than the desired frequency, the value for the desired frequency provided to selector 121 is increased so as to increase the operating voltage.
After providing the new VID value to regulator 105 in state 303, control transfers to state 305 where it monitors an indication of temperature from sensor 127 and desired frequency from register 129. If there is a change in either of these, control transfers to state 307 where it generates a new VID value.
In other embodiments, a state machine may have other configurations. In some embodiments, where regulator 105 produces multiple voltages, controller 123 may institute a state machine for each separate voltage domain. In another embodiment, controller 123 may monitor and generate a new operating voltage for each operating voltage being provided in response to a change in either temperature or desired frequency. Still in other embodiments, control of the VID generation may be made by other techniques other than a state machine. In some embodiments, controller may be implemented as hardwired logic, but in other embodiments, it may be implemented by a processor core executing programmed code.
In operation 401, an integrated circuit such as integrated circuit 101 that includes a data processor such as data processor 103 is manufactured according to conventional integrated circuit manufacturing processes such as performing semiconductor manufacturing processes on a semiconductor wafer.
In operation 403, production testing is performed on the data processor. Production testing may include performing operating voltage to operating frequency tests on the processor to determine rated frequencies of the data processor. Alternate or additional tests may be performed to determine the frequency versus voltage versus temperature characteristics of the integrated circuit 101 or frequency monitoring circuitry in the processor 103. Examples of these tests include AC scan, logic or array BIST, and ring oscillator performance test of the frequency monitoring circuitry.
In operation 405, VID/temperature/frequency values for all possible longevity values such as those shown in
In operation 407, the desired longevity value is programmed into register 131 based on a customer's desire for longevity. In some embodiments, operation 407 maybe done by the IC manufacturer, may be done by the system manufacturer, or may be done by the customer. Still in some embodiments, operation 407 may be performed by the final system during operation, such as during an initialization of the system.
In one embodiment, data of operation 405 may be loaded into memory 125 during the manufacture of the processor. For example, the data of the tables of
During operation, controller 123 reads a desired performance state from utilization register 132 and the temperature indication and selects an operating frequency identifier value and VID value from the table as determined by the longevity value. The VID value is then outputted to voltage regulator 105 and the operating frequency indentifier value is outputted to clock circuit 118.
In one embodiment, a performance state is a value provided by the operating system that indicates a particular performance level of a processor core, processor cores, or of the processor in general. For example, during an operation when all cores of data processor 103 are executing, an operating system may submit a high performance state to controller 123 where all of the cores are operating at the highest possible operating frequency. However, if the system is in a low power mode or in a power saving mode, then the operating system may request a lower performance state which translates into a lower operating frequency. The VID values would be selected which enable the core to operate at the desired operating frequency provided to clock circuit 118. In the embodiment shown, the possible operating frequencies and operating voltages assigned to a different performance state is modifiable based upon the desired longevity of the part.
As shown in the graph, the maximum voltage that can be supplied to the data processor (IC max) is 1.35 volts. If a ten year longevity is desired, then for a 95 degree operating temperature, the maximum permitted voltage is 1.0 volt. If a seven year longevity is desired, then for a 95 degree operating temperature, the maximum permitted voltage is 1.15 volts. If 3 year longevity is desired, then for a 95 degree operating temperature, the maximum permitted voltage is 1.32 volts.
Because the curves are implemented in the data of memory 125, the VID value provided by selector 121 will not indicate a higher voltage than allowed by the selected curve for a given measured temperature. However, a VID value for a voltage less than the maximum temperature may be outputted if the desired frequency can be obtained at a lower operating voltage.
Referring to the embodiment of
Although not shown, a maximum frequency curve versus indicated temperature for each longevity value may be enforced by selector 121. For example, at a particular measured temperature, a maximum operating frequency allowable for a 3 year desired longevity may be higher than for a 5 year desired longevity. Thus, the information of memory 125 is configured to enforce maximum frequency curves as well.
Line 701 indicates a maximum operating voltage allowable per operating temperature to ensure a particular longevity of the device. Because the number of operating cores translates to a particular temperature or range of operating temperatures, the maximum operating voltage allowable is dependent upon the number of cores operating at a particular time. Accordingly, the number of cores operating at one time can be used by selector 121 as an indication of the operating temperature of a device. Thus, the VID values and operating frequency values can be selected based on the number of cores operating. Information regarding the number of cores operating may be written to a utilization register 132 by the operating system.
Providing a system that allows for operating voltage (and/or operating frequency) to be selected based on a programmable longevity value provides for a data processing system that can be flexibly programmed based on the system manufacture's needs. For example, some system manufactures may use a data processor in an application (such as a cellular phone) that will have a relatively short useful life. Hence increased performance can be implemented at the expense of the useful life of the processor. Other system manufactures (such as automobile manufactures) may use the processor in a system that has a relatively long useful life. Thus, it is important for the processor to operate at a level that will ensure a long operating life. By providing a longevity value, a data processing manufacture can use one processor design for multiple system customers.
In some embodiments, selector 121 provides operating frequency identifier or identifiers and does not provide voltage identifiers to a voltage regulator.
The steps of “providing” in the method claims can be read on possession or use of a processor with the features of the claims.
In one embodiment, a processor includes at least one processor core for processing information. The processor receives an operating voltage for powering circuitry of the processor. The processor includes a selector configured to receive at least a value indicative of a temperature within the processor and configured to receive a value from a plurality of possible longevity values that each indicate a predetermined desired longevity of valid operation of the processor. The selector is configured to provide an identifier selected from a plurality of identifiers. The identifier controls at least one of a group consisting of the operating voltage and an operating frequency of the processor. The identifier provided is selected from the plurality of identifiers at least based on the value indicative of temperature and the predetermined desired longevity. The processor includes a storage device coupled to the selector for storing the value from the plurality of possible longevity values that each indicate the predetermined desired longevity of valid operation of the processor.
In another embodiment, a method includes providing a processor with at least one processor core for processing information by the processor when powered including being powered by at least one operating voltage. The method includes providing a selector of the processor configured to receive a temperature indication representing a temperature associated with the processor. The selector is configured to receive a selected longevity value from a plurality of possible longevity values indicating a desired longevity of valid operation of the processor. The selector of the processor has an output to provide an identifier selected from a plurality of identifiers based at least upon the temperature indication and the selected longevity value, the identifier controlling at least one of a group consisting of an operating voltage of the processor and an operating frequency of the processor.
In another embodiment, a processor includes a plurality of processor cores. Each of the plurality of processor cores processing information when being powered by an operating voltage. The processor includes a temperature sensor configured to provide a value indicative of a temperature within the processor. The processor includes a selector configured for receiving the value indicative of the temperature within the processor and configured for receiving a longevity value of a plurality of possible longevity values that each indicate a predetermined desired longevity of valid operation of the processor. The selector configured to provide at least one of a group consisting of a voltage identifier that controls an operating voltage of circuitry of at least one of the plurality of processor cores and a frequency identifier that controls an operating frequency of at least one of the plurality of processor cores. The processor includes a one time programmable storage device for storing the longevity value.
While particular embodiments of the present invention have been shown and described, it will be recognized to those skilled in the art that, based upon the teachings herein, further changes and modifications may be made without departing from this invention and its broader aspects, and thus, the appended claims are to encompass within their scope all such changes and modifications as are within the true spirit and scope of this invention.
