Abstract: An apparatus includes a processor circuit that includes a memory circuit, one or more processor cores, and a debug circuit. The debug circuit may be configured, in response to activation of a trace mode to record information indicative of instructions executing on the one or more processor cores, to write a trace data stream to the memory circuit that includes trace data collected on the instructions executing on the one or more processor cores. In response to a particular instruction within one of the processor cores specifying a write of a data value to an architecturally visible trace register, the debug circuit may be further configured to output the data value to the trace data stream as part of executing the particular instruction.

Abstract: An apparatus includes a plurality of processor circuits, a cache memory circuit, and a trace control circuit. The trace control circuit may be configured, in response to activation of a mode to record information indicative of program execution of at least one processor circuit of the plurality of processor circuits, to monitor memory requests transmitted between ones of the plurality of processor circuits and the cache memory circuit, and then to select a particular memory request of monitored memory requests using an arbitration algorithm. The trace control circuit may be further configured to allocate space in a trace buffer to the particular memory request, and to store, in the trace buffer, information associated with the particular memory request.

Abstract: An apparatus includes a plurality of processor circuits, a cache memory circuit, and a trace control circuit. The trace control circuit may be configured, in response to activation of a mode to record information indicative of program execution of at least one processor circuit of the plurality of processor circuits, to monitor memory requests transmitted between ones of the plurality of processor circuits and the cache memory circuit, and then to select a particular memory request of monitored memory requests using an arbitration algorithm. The trace control circuit may be further configured to allocate space in a trace buffer to the particular memory request, and to store, in the trace buffer, information associated with the particular memory request.

Abstract: An apparatus includes an execute circuit configured to execute a plurality of operations received from a queue, as well as a power estimator circuit, and a power sensing circuit. The power estimator circuit is configured to predict power consumption due to execution of a particular operation of the plurality of operations, and to withdraw, based on the predicted power consumption, a first amount of power credits from a power credit pool. The power sensing circuit is configured to monitor one or more characteristics of a power supply node coupled to the execute circuit to generate a power value, and to deposit a second amount of power credits into the power credit pool. The second amount of power credits may be based on the power value indicating that power consumed during the execution of the particular operation is less than the predicted power consumption.

Abstract: An apparatus includes a plurality of processor circuits, a cache memory circuit, and a trace control circuit. The trace control circuit may be configured, in response to activation of a mode to record information indicative of program execution of at least one processor circuit of the plurality of processor circuits, to monitor memory requests transmitted between ones of the plurality of processor circuits and the cache memory circuit, and then to select a particular memory request of monitored memory requests using an arbitration algorithm. The trace control circuit may be further configured to allocate space in a trace buffer to the particular memory request, and to store, in the trace buffer, information associated with the particular memory request.

Abstract: An apparatus includes an execute circuit configured to execute a plurality of operations received from a queue, as well as a power estimator circuit, and a power sensing circuit. The power estimator circuit is configured to predict power consumption due to execution of a particular operation of the plurality of operations, and to withdraw, based on the predicted power consumption, a first amount of power credits from a power credit pool. The power sensing circuit is configured to monitor one or more characteristics of a power supply node coupled to the execute circuit to generate a power value, and to deposit a second amount of power credits into the power credit pool. The second amount of power credits may be based on the power value indicating that power consumed during the execution of the particular operation is less than the predicted power consumption.

Abstract: An apparatus includes an execute circuit configured to execute a plurality of operations received from a queue, as well as a power estimator circuit, and a power sensing circuit. The power estimator circuit is configured to predict power consumption due to execution of a particular operation of the plurality of operations, and to withdraw, based on the predicted power consumption, a first amount of power credits from a power credit pool. The power sensing circuit is configured to monitor one or more characteristics of a power supply node coupled to the execute circuit to generate a power value, and to deposit a second amount of power credits into the power credit pool. The second amount of power credits may be based on the power value indicating that power consumed during the execution of the particular operation is less than the predicted power consumption.

Abstract: Systems, apparatuses, and methods for implementing an optimized adaptive thermal control mechanism for an integrated circuit (IC) are described. A control unit receives a digital input value which is representative of a temperature of an IC. The control unit compares the input value to at least two set points. A result of a first comparison determines whether an accumulator is incremented or decremented by a programmable gain value. A result of a second comparison determines whether the accumulator is primed with a preset ramp-up value. The preset ramp-up value is used since the accumulator can take several sensing cycles to reach the optimal control value while thermal gradients can become critical in only a few cycles. The output of the accumulator is provided to an actuator which adjusts parameter(s) to modulate the IC's temperature. The granularity and range of the accumulator matches the granularity and range of the actuator.

Abstract: An apparatus includes an execute circuit configured to execute a plurality of operations received from a queue, as well as a power estimator circuit, and a power sensing circuit. The power estimator circuit is configured to predict power consumption due to execution of a particular operation of the plurality of operations, and to withdraw, based on the predicted power consumption, a first amount of power credits from a power credit pool. The power sensing circuit is configured to monitor one or more characteristics of a power supply node coupled to the execute circuit to generate a power value, and to deposit a second amount of power credits into the power credit pool. The second amount of power credits may be based on the power value indicating that power consumed during the execution of the particular operation is less than the predicted power consumption.

Abstract: Systems, apparatuses, and methods for implementing an optimized adaptive thermal control mechanism for an integrated circuit (IC) are described. A control unit receives a digital input value which is representative of a temperature of an IC. The control unit compares the input value to at least two set points. A result of a first comparison determines whether an accumulator is incremented or decremented by a programmable gain value. A result of a second comparison determines whether the accumulator is primed with a preset ramp-up value. The preset ramp-up value is used since the accumulator can take several sensing cycles to reach the optimal control value while thermal gradients can become critical in only a few cycles. The output of the accumulator is provided to an actuator which adjusts parameter(s) to modulate the IC's temperature. The granularity and range of the accumulator matches the granularity and range of the actuator.

Abstract: An apparatus includes a functional circuit, including a power supply node, and a test circuit. The functional circuit is configured to operate in a test mode that includes generating respective test output patterns in response to application of a plurality of test stimulus patterns. The test circuit is configured to identify a particular test stimulus pattern of the plurality of test stimulus patterns, and to reapply the particular test stimulus pattern to the functional circuit multiple times. The test circuit is further configured to vary, for each reapplication, a start time of the particular test stimulus pattern in relation to when a voltage level of the power supply node is sampled for that reapplication.

Abstract: An apparatus includes a functional circuit, including a power supply node, and a test circuit. The functional circuit is configured to operate in a test mode that includes generating respective test output patterns in response to application of a plurality of test stimulus patterns. The test circuit is configured to identify a particular test stimulus pattern of the plurality of test stimulus patterns, and to reapply the particular test stimulus pattern to the functional circuit multiple times. The test circuit is further configured to vary, for each reapplication, a start time of the particular test stimulus pattern in relation to when a voltage level of the power supply node is sampled for that reapplication.

Abstract: In an embodiment, an integrated circuit includes a first circuit and a characterization circuit to capture a histogram of the supply voltage magnitude to the first circuit (or other characteristics of the first circuit). In various embodiments, the characterization circuit may: be located near the first circuit; include a sample/hold circuit that may sample the supply voltage in a short window of time and an ADC that is configured to converge to the sampled voltage over multiple orders of magnitude longer than the short window; be relatively small and low power; capture multiple histograms, e.g. one for each mode of the first circuit; support a blackout interval during mode changes; support a zoom feature to a subrange of supply voltage disabled with fine-grain histogram buckets; and/or include one or more comparators to detect maximum and/or minimum voltages experienced over a time interval.

Abstract: In an embodiment, an integrated circuit includes a first circuit and a characterization circuit to capture a histogram of the supply voltage magnitude to the first circuit (or other characteristics of the first circuit). In various embodiments, the characterization circuit may: be located near the first circuit; include a sample/hold circuit that may sample the supply voltage in a short window of time and an ADC that is configured to converge to the sampled voltage over multiple orders of magnitude longer than the short window; be relatively small and low power; capture multiple histograms, e.g. one for each mode of the first circuit; support a blackout interval during mode changes; support a zoom feature to a subrange of supply voltage disabled with fine-grain histogram buckets; and/or include one or more comparators to detect maximum and/or minimum voltages experienced over a time interval.

Abstract: In some embodiments, a system may include at least one voltage controller. At least one of the voltage controllers may assess, during use, an occurrence of a predetermined condition. In some embodiments, the system may include an at least first capacitor. The at least first capacitor may be coupled to at least one of the voltage controllers such that at least one of the voltage controllers engages the at least first capacitor to supply additional current when the predetermined condition occurs. When the increase in current is no longer required the at least first capacitor may be disengaged. The at least first capacitor may be charged when disengaged until a predetermined capacity.

Abstract: In some embodiments, a system may include at least one voltage controller. At least one of the voltage controllers may assess, during use, an occurrence of a predetermined condition. In some embodiments, the system may include an at least first capacitor. The at least first capacitor may be coupled to at least one of the voltage controllers such that at least one of the voltage controllers engages the at least first capacitor to supply additional current when the predetermined condition occurs. When the increase in current is no longer required the at least first capacitor may be disengaged. The at least first capacitor may be charged when disengaged until a predetermined capacity.

Abstract: A multiprocessor system maintains cache coherence among processors in a coherent domain. Within the coherent domain, a first processor can receive a command to perform a cache maintenance operation. The first processor can determine whether the cache maintenance operation is a coherent operation. For coherent operations, the first processor sends a coherent request message for distribution to other processors in the coherent domain and can cancel execution of the cache maintenance operation pending receipt of intervention messages corresponding to the coherent request. The intervention messages can reflect a global ordering of coherence traffic in the multiprocessor system and can include instructions for maintaining a data cache and an instruction cache of the first processor. Cache maintenance operations that are determined to be non-coherent can be executed at the first processor without sending the coherent request.

Abstract: The present invention provides a clock ratio controller for dynamic voltage and frequency scaled digital systems, and applications thereof. In an embodiment, a digital system is provided that includes a first digital circuit that operates at a first rate determined by a first clock signal and a second digital circuit that operates at a second rate determined by a second clock signal. The first digital circuit is coupled to the second digital circuit by a bus that is used for communications between the first digital circuit and the second digital circuit. A clock ratio controller is used to adjust the frequency of the first clock signal and/or the second clock signal in response to a power management signal without causing a loss of synchronization between the first digital circuit and the second digital circuit.

Abstract: A method of fetching data from a cache begins by preparing to fetch a first set of cache ways for a first data word of a first cache line a using a first thread. Next, in parallel, a second set cache ways for a first data word of a second cache line is prepared to be fetched using a second thread, and data associated with each cache way of the first set of cache ways are fetched using the first thread. Also performed in parallel, data associated with each cache way of the second set of cache ways is fetched using the second thread and a third set of cache ways for a second data word of the first cache line is prepared to be fetched using the first thread based on a selected cache way, the selected cache way selected from the first set of cache ways.

Abstract: The present invention provides a clock ratio controller for dynamic voltage and frequency scaled digital systems, and applications thereof. In an embodiment, a digital system is provided that includes a first digital circuit that operates at a first rate determined by a first clock signal and a second digital circuit that operates at a second rate determined by a second clock signal. The first digital circuit is coupled to the second digital circuit by a bus that is used for communications between the first digital circuit and the second digital circuit. A clock ratio controller is used to adjust the frequency of the first clock signal and/or the second clock signal in response to a power management signal without causing a loss of synchronization between the first digital circuit and the second digital circuit.