[Openmp-commits] [PATCH] D21196: Excluded untied tasks from task stealing constraint

[Andrey Churbanov via Openmp-commits]

AndreyChurbanov added inline comments.


================
Comment at: openmp/trunk/runtime/src/kmp_tasking.c:1754
         }
-        if ( parent != current ) {
+        if ( parent != current && (taskdata->td_flags.tiedness == TASK_TIED) ) { // untied is always allowed to be stolen
             // If the tail task is not a child, then no other childs can appear in the deque (?).
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pawosm01 wrote:
> This line causes race condition which leads to occasional livelock in strassen_taskdep benchmark from Kastors suite (a benchmark that heavily uses task dependencies). Could be replicated on AArch64 and x86_64, typically working on odd number of cores (5, 7, etc.).
> 
I agree the change in this line is a bug.  But once it has beed committed, could you please advise how to better fix the issue?

Is it OK to create new review request that reverts the change in this line and close current one?

Or should I revert both changes and re-submit the diff with only the first change that looks OK?

Or can I just revert the change in this line and close the review without changing the diff?

Thanks, Andrey


Repository:
  rL LLVM

https://reviews.llvm.org/D21196