Intel® oneAPI Threading Building Blocks
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large overhead in "manual reset event"

intelbenz
Beginner
139 Views
Just recently I update my tbb 2.1 to tbb 3.0.
And I also switch my pthreads to tbb tasks after reading the
following article

http://software.intel.com/en-us/articles/using-tasks-instead-of-threads/

After taking an analysis on the "locks and waits" I found out that
my program ran slower and having a significant overhead on the
"manual reset event", the wait time was about 6s.

Could anyone what went wrong ?

thanks!

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2 Replies
Dmitry_Vyukov
Valued Contributor I
139 Views
AFAIR, manual reset event is used to park worker threads in TBB. So perhaps your program does not yield enough parallelism, so that some worker threads are parked.
Dmitry_Vyukov
Valued Contributor I
139 Views
Check the call stack for the wait on manual reset event.
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