Implicit multi-threading issue

ROOT
21

Hi,

I think that would be an interesting Topical meeting. I’d prefer to shift it to after the 6.16 release if possible.

Cheers,
D

22

This topic was automatically closed 14 days after the last reply. New replies are no longer allowed.

23

Hi,
just to give a conclusion to the thread: as of ROOT versions 6.14/06 and 6.16, nested execution of TBB tasks has been disabled in ROOT’s implicit multi-threading, following the technique described in Attila’s link above ( https://www.threadingbuildingblocks.org/docs/help/tbb_userguide/work_isolation.html)

What this means concretely is that RDataFrame processes events sequentially in each thread, resolving the issue discussed here, removing the requirement of reentrancy on user-defined operations, and generally making the mental model saner.

Thanks a lot to @Attila_Krasznahorkay and @pcanal for the super useful feedback.
Cheers,
Enrico

25

To add to the previous statements of Enrico, which I fully support, the talk summarising those efforts at the “Experiments and ROOT Meeting” can be found here: https://indico.cern.ch/event/773968

Cheers,
Danilo