Perceive Corporation

Adeia Semiconductor Bonding Technologies Inc.

Amazon Technologies, Inc.

Intel Corporation

Adeia Semiconductor Inc.

Tahoe Research, Ltd.

Kenneth Duong

Steven L Teig

Jung Ko

Javier A DeLaCruz

Ilyas Mohammed

Eric Nequist

Won Rhee

Liang Wang

David Edward Fisch

Trevis Chandler

Dipak Sikdar

Javier A Delacruz

Xu Chang

Some embodiments of the invention provide a three-dimensional (3D) circuit that is formed by vertically stacking two or more integrated circuit (IC) dies to at least partially overlap. In this arrangement, several circuit blocks defined on each die (1) overlap with other circuit blocks defined on one or more other dies, and (2) electrically connect to these other circuit blocks through connections that cross one or more bonding layers that bond one or more pairs of dies. In some embodiments, the overlapping, connected circuit block pairs include pairs of computation blocks and pairs of computation and memory blocks. The connections that cross bonding layers to electrically connect circuit blocks on different dies are referred to below as z-axis wiring or connections. This is because these connections traverse completely or mostly in the z-axis of the 3D circuit, with the x-y axes of the 3D circuit defining the planar surface of the IC die substrate or interconnect layers. These connections are also referred to as vertical connections to differentiate them from the horizontal planar connections along the interconnect layers of the IC dies.

3D processor having stacked integrated circuit die

Some embodiments provide an IC for implementing a machine-trained network with multiple layers. The IC includes a set of circuits to compute a dot product of (i) a first number of input values computed by other circuits of the IC and (ii) a set of predefined weight values, several of which are zero, with a weight value for each of the input values. The set of circuits includes (i) a dot product computation circuit to compute the dot product based on a second number of inputs and (ii) for each input value, at least two sets of wires for providing the input value to at least two of the dot product computation circuit inputs. The second number is less than the first number. Each input value with a corresponding weight value that is not equal to zero is provided to a different one of the dot product computation circuit inputs.

Reduced dot product computation circuit

Some embodiments provide a method for a circuit that executes a neural network including multiple nodes. The method loads a set of weight values for a node into a set of weight value buffers, a first set of bits of each input value of a set of input values for the node into a first set of input value buffers, and a second set of bits of each of the input values into a second set of input value buffers. The method computes a first dot product of the weight values and the first set of bits of each input value and a second dot product of the weight values and the second set of bits of each input value. The method shifts the second dot product by a particular number of bits and adds the first dot product with the bit-shifted second dot product to compute a dot product for the node.

Computation of neural network node with large input values

Some embodiments provide a three-dimensional (3D) circuit structure that has two or more vertically stacked bonded layers with a machine-trained network on at least one bonded layer. As described above, each bonded layer can be an IC die or an IC wafer in some embodiments with different embodiments encompassing different combinations of wafers and dies for the different bonded layers. The machine-trained network in some embodiments includes several stages of machine-trained processing nodes with routing fabric that supplies the outputs of earlier stage nodes to drive the inputs of later stage nodes. In some embodiments, the machine-trained network is a neural network and the processing nodes are neurons of the neural network. In some embodiments, one or more parameters associated with each processing node (e.g., each neuron) is defined through machine-trained processes that define the values of these parameters in order to allow the machine-trained network (e.g., neural network) to perform particular operations (e.g., face recognition, voice recognition, etc.). For example, in some embodiments, the machine-trained parameters are weight values that are used to aggregate (e.g., to sum) several output values of several earlier stage processing nodes to produce an input value for a later stage processing node.

Three dimensional circuit implementing machine trained network

Some embodiments provide a method that receives a specification of a neural network for execution by an integrated circuit. The integrated circuit includes a neural network inference circuit for executing the neural network to generate an output based on an input, an input processing circuit for providing the input to the neural network inference circuit, a microprocessor circuit for controlling the neural network inference circuit and the input processing circuit, and a unified memory accessible by the microprocessor circuit, the neural network inference circuit, and the input processing circuit. The method determines usage of the unified memory by the neural network inference circuit while executing the neural network. Based on the determined usage by the neural network inference circuit, the method allocates portions of the unified memory to the microprocessor circuit and input processing circuit.

Allocating blocks of unified memory for integrated circuit executing neural network

Some embodiments provide a neural network inference circuit (NNIC) for executing a neural network that includes multiple computation nodes at multiple layers. The NNIC includes a set of clusters of core computation circuits and a channel, connecting the core computation circuits, that includes separate segments corresponding to each of the clusters. The NNIC includes a fabric controller circuit, a cluster controller circuit for each of the clusters, and a core controller circuit for each of the core computation circuits. The fabric controller circuit receives high-level neural network instructions from a microprocessor and parses the high-level neural network instructions.

Computation of neural network node by neural network inference circuit

Some embodiments provide a neural network inference circuit for executing a neural network that includes multiple layers of computation nodes. At least a subset of the layers include non-convolutional layers. The neural network inference circuit includes multiple cores with memories that store input values for the layers. The cores are grouped into multiple clusters. For each cluster, the neural network inference circuit includes a set of processing circuits for receiving input values from the cores of the cluster and executing the computation nodes of the non-convolutional layers.

Data transfer for non-dot product computations on neural network inference circuit

Some embodiments provide a method for executing a neural network. The method writes a first input to a first set of physical memory banks in a unified memory shared by an input processing circuit and a neural network inference circuit that executes the neural network. While the neural network inference circuit is executing the network a first time to generate a first output for the first input, the method writes a second input to a second set of physical memory banks in the unified memory. The neural network inference circuit executes a same set of instructions to read the first input from the first set of memory banks in order to execute the network the first time and to read the second input from the second set of memory banks in order to execute the network a second time to generate a second output for the second input.

Buffering of neural network inputs and outputs

Some embodiments provide a method for a neural network inference circuit that executes a neural network including multiple computation nodes at multiple layers. Each computation node of a set of the computation nodes includes a dot product of input values and weight values. The method reads a set of encoded weight data for a set of weight values from a memory of the neural network inference circuit. The method decodes the encoded weight data to generate decoded weight data for the set of weight values. The method stores the decoded weight data in a buffer. The method uses the decoded weight data to execute a set of computation nodes. Each computation node of the set of computation nodes includes a dot product between the set of weight values and a different set of input values.

Weight value decoder of neural network inference circuit

Some embodiments provide a neural network inference circuit (NNIC) for executing a neural network that includes multiple computation nodes at multiple layers. The NNIC includes multiple core circuits including memories for storing input values for the computation nodes. The NNIC includes a set of post-processing circuits for computing output values of the computation nodes. The output values for a first layer are for storage in the core circuits as input values for a second layer. The NNIC includes an output bus that connects the post-processing circuits to the core circuits. The output bus is for (i) receiving a set of output values from the post-processing circuits, (ii) transporting the output values of the set to the core circuits based on configuration data specifying a core circuit at which each of the output values is to be stored, and (iii) aligning the output values for storage in the core circuits.

Bus for transporting output values of a neural network layer to cores specified by configuration data

For a neural network inference circuit that executes a neural network including multiple computation nodes at multiple layers for which data is stored in a plurality of memory banks, some embodiments provide a method for dynamically putting memory banks into a sleep mode of operation to conserve power. The method tracks the accesses to individual memory banks and, if a certain number of clock cycles elapse with no access to a particular memory bank, sends a signal to the memory bank indicating that it should operate in a sleep mode. Circuit components involved in dynamic memory sleep, in some embodiments, include a core RAM pipeline, a core RAM sleep controller, a set of core RAM bank select decoders, and a set of core RAM memory bank wrappers.

Neural network inference circuit employing dynamic memory sleep

Some embodiments provide a method for a neural network inference circuit that executes a neural network. The method loads a first set of inputs into an input buffer and computes a first dot product between the first set of inputs and a set of weights. The method shifts the first set of inputs in the buffer while loading a second set of inputs into the buffer such that a first subset of the first set of inputs is removed from the buffer, a second subset of the first set of inputs is moved to new locations in the buffer, and a second set of inputs are loaded into locations in the buffer vacated by the shifting. The method computes a second dot product between (i) the second set of inputs and the second subset of the first set of inputs and (ii) the set of weights.

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San Jose, CA, United States of America

Kenneth Duong