Technical data

Glossary
latency: The time that elapses from an element entering a pipeline until the
first result is produced.
linear recurrence: A cyclic data dependency in a linear function.
LINPACK: An industry-wide benchmark used to measure the performance
characteristics of various computers. Unlike some benchmarks, LINPACK is
a real application package doing linear algebra calculations.
Livermore FORTRAN kernels: A set of loops used to measure the performance
characteristics of various computers and the efficiency of vectorizing
compilers. The 24 kernels are fragments of programs from scientific and
engineering applications. Also known as Livermore Loops.
loop fusion: A transformation that takes two separate DO loops and makes a
single DO loop one out of them.
loop rolling: A transformation that combines parts of DO loops to allow for
vectorization.
loop unrolling: A transformation that separates certain DO loops into smaller
loops to reduce overhead.
loop-carried dependency: A data dependency that crosses iteration
boundaries or that crosses between a loop and serial code. The dependency
would not exist in the absence of the loop.
loop-independent dependency: A data dependency that occurs whether or not
a loop iterates.
mask register: A vector control register used to select the elements of a vector
that will participate in a particular operation.
megaflops: A measure of the performance of a computer—the rate at which
the computer executes floating-point operations. Expressed in terms of
"millions of floating-point operations per second." Known as MFLOPS.
memory bandwidth: The range of speeds at which a memory bus or path
can carry data. The lowest speed is usually 0 (no data) and is, therefore
normally not mentioned. For example, a memory bus that can provide data
at speeds from 0 to 512 megabytes per second is said to have a bandwidth of
512 Mbytes/s.
memory bank: An individual memory board. Groups of memory banks make
up interleaved high-speed main memory.
Glossary–3