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I am compiling intel tbb community version tbb2017_20161128oss. While compiling it runs few test cases. in one of the test case it gives me the warning ./test_global_control.exe
TBB Warning: The number of workers is currently limited to 0. The request for 1 workers is ignored. Further requests for more workers will be silently ignored until the limit changes.

What does this warning mean for my platform? Should I refrain from using certain components of ITBB?

Some programmer dude
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user2020871
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    If you ask about something platform specific, it helps to tell *what* platform you're talking about. It can be inferred from the command you're using (since it ends with `.exe`) but then you use `./` which is uncommon in platforms that have programs with `.exe` endings. – Some programmer dude Feb 09 '17 at 08:02
  • I am running on Linux bash shell ptompt – user2020871 Feb 19 '17 at 02:32

1 Answers1

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Usually for TBB tests you can ignore run-time warnings starting from "TBB warning". Generally, these warnings are to tell programmers that they possibly use TBB sub-optimally or incorrectly. In the tests, however, the library is used in very complicated ways, and so sometimes warnings are issued.

This particular warning tells that a program first has limited the number of worker threads allowed to use, and then tries to request more workers than the limit allows. For the test, it's important to check that the behavior is correct in such corner cases; but the warning is outside of its control.

In real applications, these warnings can help diagnosing unexpected situations, and so should not be ignored.

Alexey Kukanov
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  • Thanks for the reply. – user2020871 Feb 27 '17 at 13:04
  • But My concern is, Why the Number of workers are limited to zero. If I am not wrong one of the parameter for deciding No of workers is number of hardware threads(cores) the system has. I am compiling ITBB on the machine which has 4 threads, still it is showing number of workers as zero. So My query is am missing something during compilation, or it is just at the time of test, ITBB library is not able to get the resources because of other applications running. – user2020871 Feb 27 '17 at 13:15
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    There are TBB classes for explicit control over the number of workers being used, in particular the class tbb::global_control. The test uses it to prevent use of worker threads, for the sake of testing. So, do not be worried about it. – Alexey Kukanov Mar 02 '17 at 16:41
  • Thank you very much – user2020871 Mar 10 '17 at 09:53
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    You are welcome. On StackOverflow, it is recommended to up-vote useful answers and accept the one that you think addresses your question best; see more here: http://stackoverflow.com/help/someone-answers – Alexey Kukanov Mar 10 '17 at 10:28