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gputimeit

Time required to run function on GPU

Syntax

t = gputimeit(F)
t = gputimeit(F,N)

Description

t = gputimeit(F) measures the typical time (in seconds) required to run the function specified by the function handle F. The function handle accepts no external input arguments, but can be defined with input arguments to its internal function call.

t = gputimeit(F,N) calls F to return N output arguments. By default, gputimeit calls the function F with one output argument, or no output arguments if F does not return any output.

Examples

Measure the time to calculate sum(A.' .* B, 1) on a GPU, where A is a 12000-by-400 matrix and B is 400-by-12000.

A = rand(12000,400,'gpuArray');
B = rand(400,12000,'gpuArray');
f = @() sum(A.' .* B, 1);
t = gputimeit(f)
0.0026

Compare the time to run svd on a GPU, with one versus three output arguments.

X = rand(1000,'gpuArray');
f = @() svd(X);
t3 = gputimeit(f,3)
1.0622
t1 = gputimeit(f,1)
0.2933

More About

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Tips

gputimeit is preferable to timeit for functions that use the GPU, because it ensures that all operations on the GPU have finished before recording the time and compensates for the overhead. For operations that do not use a GPU, timeit offers greater precision.

Note the following limitations:

  • The function F should not call tic or toc.

  • You cannot use tic and toc to measure the execution time of gputimeit itself.

See Also

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