Add an option to set number of warmup iterations

[wojtuss]

PR types

Others

PR changes

Others

Describe

With this patch one can set the number of iterations for warmup phase in performance tests. When the option --warmup=true is used, by default one iteration of inference is run as a warmup. Now, with additional option --warmup_iters=5 the given number of iterations will be run in warmup.
This option helps properly measure performance of GRU FP32/INT8 model with oneDNN. When running GRU inference with oneDNN, the oneDNN cache needs more than one (actually close to 20) iterations to cache all the primitives required during inference of the whole dataset.

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[luotao1]

Does this PR make the elapsed time of the unit-test become longer since each unit-test has an extra warmup iteration? Could the default warmup_iter be 0?

[wojtuss]

Does this PR make the elapsed time of the unit-test become longer since each unit-test has an extra warmup iteration? Could the default warmup_iter be 0?

@luotao1
The option --wamup_iters only changes the number of warmup iterations if the --warmup option is used. If the --warmup option is not used, or --warmup_iters is not used or is set to a number <=1, then it has no effect (i.e. still the default number of warmup iterations (1) is used for the --warmup option). If it is set to a number >1, then yes, it has impact on execution time of the tests which use this option, because more inference iterations are executed during warmup. However, for GRU model test the warmup iterations are rather quick.

[luotao1]

Got it, thanks for your explanation.