[Openmp-commits] [openmp] 7cf63ee - [OpenMP][Docs] Add non-blocking target nowait environment variables

[Guilherme Valarini via Openmp-commits]

Author: Guilherme Valarini
Date: 2023-01-24T16:30:34-03:00
New Revision: 7cf63ee80c7588fba543136ab67d38172aedf5ed

URL: https://github.com/llvm/llvm-project/commit/7cf63ee80c7588fba543136ab67d38172aedf5ed
DIFF: https://github.com/llvm/llvm-project/commit/7cf63ee80c7588fba543136ab67d38172aedf5ed.diff

LOG: [OpenMP][Docs] Add non-blocking target nowait environment variables

Added: 
    

Modified: 
    openmp/docs/ReleaseNotes.rst

Removed: 
    


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diff  --git a/openmp/docs/ReleaseNotes.rst b/openmp/docs/ReleaseNotes.rst
index 371457aba34f..dd594263ea79 100644
--- a/openmp/docs/ReleaseNotes.rst
+++ b/openmp/docs/ReleaseNotes.rst
@@ -57,3 +57,14 @@ Non-comprehensive list of changes in this release
 
 * Fixed a number of bugs and regressions.
 
+* Improved host thread utilization on target nowait regions. Target tasks are
+  now continuously re-enqueued by the OpenMP runtime until their device-side
+  operations are completed, unblocking the host thread to execute other tasks.
+
+* Target tasks re-enqueue can be controlled on a per-thread basis based on
+  exponential backoff counting. ``OMPTARGET_QUERY_COUNT_THRESHOLD`` defines how
+  many target tasks must be re-enqueued before the thread starts blocking on the
+  device operations (defaults to 10). ``OMPTARGET_QUERY_COUNT_MAX`` defines the
+  maximum value for the per-thread re-enqueue counter (defaults to 5).
+  ``OMPTARGET_QUERY_COUNT_BACKOFF_FACTOR`` defines the decrement factor applied
+  to the counter when a target task is completed (defaults to 0.5).