Optimizing Deep Learning Computation on Inter-core Connected Intelligence Processors with T10

แนวคิดหลัก

T10 is a deep learning compiler that efficiently utilizes the distributed on-chip memory and high inter-core communication bandwidth of emerging intelligence processors to scale deep learning computation.

บทคัดย่อ

The paper presents T10, a deep learning compiler designed to optimize the execution of deep neural network (DNN) models on inter-core connected intelligence processors, such as the Graphcore IPU.
Key highlights:

T10 introduces a new tensor abstraction called RotatingTensor (rTensor) to represent the partitioning and communication patterns of tensor operators on the distributed on-chip memory. rTensor enables T10 to map DNN models to efficient compute-shift execution plans.

T10 defines a comprehensive optimization space by configuring rTensors in different ways, and adopts a two-stage optimization strategy to handle the tradeoff between inter-core communication and memory footprint. It first finds the Pareto-optimal execution plans for each operator, and then employs a holistic inter-operator memory reconciliation policy to determine the best end-to-end plan for the entire DNN model.

T10 abstracts three key device interfaces (allocate, compute, and shift) to map the optimized execution plan to the target inter-core connected AI accelerator. It also develops a sub-tensor placement algorithm to ensure data dependencies are satisfied during the rotating shifts.

Evaluation on a real Graphcore IPU MK2 chip shows that T10 can achieve up to 3.3x performance improvement and support much larger models compared to state-of-the-art DL compilers and vendor libraries.

สถิติ

The Graphcore IPU MK2 chip has 1,472 cores, each with a 624KB scratchpad memory, providing a total of 896MB on-chip memory.
The inter-core all-to-all communication bandwidth on the IPU is around 8TB/s, much higher than the HBM bandwidth of 1.94TB/s on an A100 GPU.

คำพูด

"To meet the ever-increasing compute demand of deep learning (DL) workloads, various AI chips or intelligence processors have been developed [22, 32, 33]. Typically, an AI chip employs numerous cores to provide high compute throughput."
"Instead of fetching all data from the global memory, inter-core communication links allow cores to directly reuse the data from each other, enabling higher on-chip data reuse."

ข้อมูลเชิงลึกที่สำคัญจาก

Scaling Deep Learning Computation over the Inter-Core Connected Intelligence Processor with T10

by Yiqi Liu, Yu... ที่ arxiv.org 09-25-2024

https://arxiv.org/pdf/2408.04808.pdf

สอบถามเพิ่มเติม

How can T10's techniques be extended to support other types of AI accelerators beyond the Graphcore IPU, such as GPUs or custom ASIC chips?

T10's techniques can be extended to support other AI accelerators, including GPUs and custom ASIC chips, by adapting its core principles of distributed memory management and inter-core communication to the architectural characteristics of these platforms. For GPUs, which typically utilize a global shared memory model, T10's compute-shift execution paradigm can be modified to optimize memory access patterns and reduce global memory bandwidth contention. This could involve implementing a similar rTensor abstraction that accounts for the hierarchical memory structure of GPUs, where shared memory and registers can be leveraged for faster data access.
For custom ASIC chips, T10's flexible tensor partitioning and communication strategies can be tailored to the specific interconnect architecture and memory bandwidth of the ASIC. By analyzing the unique characteristics of the ASIC, such as the number of cores, memory architecture, and communication bandwidth, T10 can generate optimized execution plans that maximize data locality and minimize communication overhead. Additionally, the cost model developed in T10 can be adapted to reflect the performance characteristics of these accelerators, ensuring that the optimization process remains effective across different hardware platforms.

What are the potential challenges in integrating T10 into existing deep learning frameworks and deployment pipelines?

Integrating T10 into existing deep learning frameworks and deployment pipelines presents several challenges. First, compatibility with existing frameworks such as TensorFlow or PyTorch is crucial. T10 would need to provide seamless interfaces or APIs that allow users to leverage its capabilities without significant changes to their existing codebases. This may require extensive modifications to the frameworks to accommodate T10's unique tensor abstractions and execution plans.
Second, the complexity of T10's optimization processes, including the cost model and the two-level trade-off space, may introduce additional overhead in terms of compilation time and resource management. Users may need to balance the benefits of optimized execution against the potential increase in compilation time, which could affect the overall workflow in production environments.
Third, ensuring that T10 can handle a wide variety of tensor operations and model architectures is essential for broad adoption. The integration process must include comprehensive testing and validation to ensure that T10 can effectively optimize diverse deep learning models without introducing errors or performance regressions.
Finally, there may be challenges related to hardware compatibility and performance tuning. Different AI accelerators have unique characteristics that may require specific tuning of T10's optimization strategies to achieve optimal performance. This necessitates a deep understanding of the underlying hardware and may require collaboration with hardware vendors to refine T10's capabilities.

How can the compute-shift execution paradigm introduced in T10 be further optimized or generalized to support a wider range of tensor operations beyond the ones covered in this work?

The compute-shift execution paradigm can be further optimized and generalized to support a wider range of tensor operations by enhancing its flexibility and adaptability to various computational patterns. One approach is to develop a more sophisticated rTensor abstraction that can accommodate different types of tensor operations, such as reductions, element-wise operations, and more complex operations like recurrent neural networks (RNNs) or attention mechanisms in transformers.
To achieve this, T10 could implement a dynamic partitioning strategy that allows for real-time adjustments to the spatial and temporal partition factors based on the specific characteristics of the tensor operation being executed. This would enable T10 to optimize the execution plan on-the-fly, adapting to varying workloads and data dependencies.
Additionally, incorporating machine learning techniques to predict optimal partitioning and communication strategies based on historical execution data could enhance the efficiency of the compute-shift paradigm. By learning from past executions, T10 could automatically adjust its execution plans to minimize communication overhead and maximize compute efficiency.
Furthermore, extending the compute-shift paradigm to support asynchronous execution and overlapping computation with communication could significantly improve performance. By allowing cores to perform computations while simultaneously shifting data, T10 could reduce idle times and improve overall throughput.
Lastly, developing a library of optimized kernels for various tensor operations that leverage the compute-shift paradigm could facilitate broader adoption. These kernels would be pre-tuned for specific operations, allowing users to easily integrate them into their models while benefiting from the optimizations provided by T10. This would not only enhance performance but also simplify the user experience when working with diverse tensor operations.