Title
A High-Performance SIMD Floating Point Unit for BlueGene/L: Architecture, Compilation, and Algorithm Design
Abstract
We describe the design, implementation, and evaluation of a dual-issue SIMD-like extension of the PowerPC 440 floating-point unit (FPU) core. This extended FPU is targeted at both IBM's massively parallel Blue-Gene/L machine as well as more pervasive embedded platforms. It has several novel features, such as a computational crossbar and cross-load/store instructions, which enhance the performance of numerical codes. We further discuss the hardware-software co-design that was essential to fully realize the performance benefits of the FPU when constrained by the memory bandwidth limitations and high penalties for misaligned data access imposed by the memory hierarchy on a BlueGene/L node. We describe several novel compiler and algorithmic techniques to take advantage of this architecture. Using both hand-optimized and compiled code for key linear algebraic kernels, we validate the architectural design choices, evaluate the success of the compiler, and quantify the effectiveness of the novel algorithm design techniques. Preliminary performance data shows that the algorithm-compiler-hardware combination delivers a significant fraction of peak floating-point performance for compute-bound kernels such as matrix multiplication, and delivers a significant fraction of peak memory bandwidth for memory-bound kernels such as daxpy, while being largely insensitive to data alignment.
Year
DOI
Venue
2004
10.1109/PACT.2004.2
IEEE PACT
Keywords
Field
DocType
algorithm design,data access,floating point arithmetic,embedded systems,linear algebra,memory bandwidth,matrix multiplication,floating point,floating point unit,instruction sets
Memory hierarchy,Memory bandwidth,Computer science,Floating point,Floating-point unit,Parallel computing,SIMD,Compiler,Real-time computing,PowerPC,Data structure alignment
Conference
ISBN
Citations 
PageRank 
0-7695-2229-7
14
3.40
References 
Authors
10
11
Name
Order
Citations
PageRank
Leonardo R. Bachega18711.25
Siddhartha Chatterjee21410153.05
Kenneth A. Dockser318025.73
John A. Gunnels471783.20
Manish Gupta559866.31
Fred G. Gustavson61185223.40
Christopher A. Lapkowski7143.40
Gary K. Liu8143.40
M. Mendell914319.11
Charles D. Wait1018025.73
T. J. Christopher Ward1125234.78