Programmazione di processori massivamente paralleli: un approccio pratico
Questo corso offre un'introduzione completa al calcolo GPU e alla programmazione parallela utilizzando l'ambiente CUDA C. Copre le architetture GPU, il parallelismo dei dati, la gestione dei thread, l'ottimizzazione della memoria e considerazioni avanzate sulle prestazioni, illustrate attraverso casi di studio reali come la ricostruzione di immagini MRI e la visualizzazione molecolare.
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📚 Riepilogo del contenuto
Questo corso offre un'introduzione completa al calcolo GPU e alla programmazione parallela tramite l'ambiente CUDA C. Copre le architetture GPU, il parallelismo dati, la gestione dei thread, l'ottimizzazione della memoria e considerazioni avanzate sulle prestazioni, illustrate attraverso casi reali come la ricostruzione di immagini MRI e la visualizzazione molecolare.
Padroneggia l'arte del calcolo parallelo ad alte prestazioni con una guida pratica e basata su esercitazioni per CUDA e le architetture GPU.
Autore: David B. Kirk, Wen-mei W. Hwu
Ringraziamenti: Ian Buck, John Nickolls, team NVIDIA DevTech, Jensen Huang, David Luebke, Bill Bean, Simon Green, Mark Harris, Manju Hedge, Nadeem Mohammad, Brent Oster, Peter Shirley, Eric Young e Cyril Zeller.
🎯 Obiettivi di apprendimento
- Distinguere tra filosofie progettuali e traiettorie di prestazioni di CPU multicore e GPU many-core.
- Identificare i componenti chiave di un'architettura GPU moderna, inclusi i Streaming Multiprocessors (SM) e le strutture di memoria.
- Applicare la legge di Amdahl per calcolare il guadagno teorico in velocità e identificare l'impatto dei colli di bottiglia sequenziali.
- Confrontare le differenze architetturali tra pipeline fisse e array di processori programmabili unificate.
- Spiegare il ruolo del "GPGPU" come passaggio intermedio e le limitazioni dei primi modelli di programmazione shader.
- Analizzare come funzionalità hardware come operazioni atomiche, sincronizzazione barriera e supporto a precisione doppia hanno permesso il passaggio al calcolo generico scalabile.
- Identificare e sfruttare il parallelismo dati all'interno degli algoritmi di moltiplicazione matrice-matrice.
- Implementare la gestione della memoria del dispositivo, inclusa l'allocazione, il trasferimento dei dati tra host e dispositivo e la deallocazione.
- Creare e lanciare kernel CUDA utilizzando indici thread appropriati e configurazioni di griglia/blocco.
- Progettare gerarchie di thread multidimensionali (griglie e blocchi) per mappare strutture dati complesse sull'hardware GPU.
Lezioni 共 12 课时 · 预计 36.0h
Lezioni
Lesson
This lesson explores the evolution of parallel computing, highlighting the "Great Divergence" where GPUs surpassed CPUs in performance by prioritizing throughput-oriented architecture over sequential latency. Students will learn to differentiate between these processing models, understand the impact of the "Power Wall" on CPU design, and analyze how GPU transistor budgeting enables massive parallel computation.
This lesson explores the evolution of GPU architecture, focusing on the "real-time imperative" that necessitated a shift from serial CPU processing to parallel hardware acceleration. Students will learn how early innovations like SLI and the "wide and slow" design philosophy enabled the high-throughput performance required to meet strict frame-time budgets in modern computing.
This lesson explores the CUDA execution model, focusing on the architectural differences between the latency-optimized CPU (Host) and the throughput-optimized GPU (Device). Students will learn how to manage the lifecycle of a CUDA kernel, implement memory allocation using cudaMalloc and cudaMemcpy, and organize threads into grids and blocks to perform parallel computations.
This lesson explores the fundamentals of CUDA kernel execution, focusing on the transition from CPU-based iteration to data-centric GPU parallelism. Students will learn to implement the global indexing formula, manage execution configurations for transparent scalability, and apply boundary guards to ensure safe memory access across multidimensional data.
This lesson explores the "Memory Wall" in GPU computing, where computational throughput outpaces memory bandwidth, creating a significant performance bottleneck. Students will learn to mitigate these constraints by implementing shared memory tiling strategies, optimizing data reuse, and managing hardware resource limits to maximize occupancy.
This lesson explores the SIMT execution model, focusing on how hardware organizes threads into 32-thread warps and linearizes them for efficient scheduling. Students will learn to evaluate performance through warp partitioning, branch divergence analysis, and memory access patterns to optimize GPU kernel utilization.
This lesson explores how Excess Encoding (biased representation) enables high-speed hardware sorting by ensuring that bit patterns maintain a monotonic relationship with their numerical values. By replacing the sign-bit discontinuity of Two's Complement with this biased format, engineers can utilize simple, efficient unsigned comparators to perform rapid operations like Z-buffering in parallel processors.
This lesson explores the computational challenges of non-Cartesian MRI reconstruction, where spiral trajectories require iterative solvers or gridding instead of standard Fast Fourier Transforms. Students will learn how to overcome these bottlenecks by leveraging GPU-based massive parallelism, specifically focusing on voxel-to-thread mapping to optimize reconstruction speed for time-sensitive clinical applications like Sodium MRI.
This lesson explores the use of Direct Coulomb Summation (DCS) and GPU acceleration to generate electrostatic potential maps for molecular visualization. Students will learn to optimize rendering pipelines through techniques like loop unrolling and constant memory broadcasting to efficiently handle large-scale atomic data.
This lesson explores the transition from sequential processing to parallel computing, emphasizing how computational thinking helps overcome the power wall and frequency limits. Students will learn to evaluate parallel algorithm performance, manage the trade-offs between numerical precision and execution speed, and apply problem decomposition to optimize distributed systems.
This lesson introduces the OpenCL framework as a solution for managing heterogeneous computing environments, where a host CPU orchestrates tasks across diverse accelerators like GPUs and FPGAs. Students will learn to utilize the OpenCL platform layer for hardware discovery, understand the device model's hierarchy, and implement portable, efficient kernels that adapt to different architectural requirements.
This lesson explores the evolution of GPU architecture from graphics-focused designs to the compute-first Fermi generation, which introduced unified memory hierarchies and IEEE 754-2008 compliance. Students will learn how these advancements, including hardware-managed caching and improved thread scheduling, enable complex scientific computing and general-purpose programming beyond traditional 2D grid tasks.