Deafult for chunk size

[abhimodak]

Hi

I am wondering what is the default value of chunk size? I ask this because I am wondering what would happen when schedule is runtime and through omp_set_schedule assigns a number less than unity for the chunksize (by mistake).

Abhi

[abhimodak]

I reported this to premier support but did not get an answer to the question....

Abhi

[Steven_L_Intel1]

What is the Premier Support issue number?

[abhimodak]

666229. You can see that the answer given is not what I have asked.

Abhi

[TimP]

It may have been difficult for someone who may not be fluent in English to guess what you meant to ask. OpenMP standard dictates what default chunk sizes are; I don't think it says what happens or specifies any required diagnostic when you set a negative value at run time.

[abhimodak]

Hi Tim

>>> I don't think it says what happens or specifies any required diagnostic when you set a negative value at run time.

That's why we want to know what Intel Fortran does. May be the behavior is of the type -- "at the mercy of compiler" i.e. unpredictable.

I understand the language barrier and definitely respect that. But a delay in getting answer can be difficult to explain to "management".

Abhi

[Steven_L_Intel1]

I asked the developers and received this response:

With static scheduling, chunk_size defaults to num_iters / num_threads (possibly +1).

With dynamic, chunk_size defaults to 1.

With guided, chunk_size defaults to 1, but that is just a lower bound on the actual assigned chunk size.

In our implementation, if the chunk size is < 1, we just set it to 1