From 45a58e4a728a699fdedc05d8163d91749baf73fa Mon Sep 17 00:00:00 2001
From: Florian Schmaus <flow@cs.fau.de>
Date: Mon, 22 Feb 2021 21:27:49 +0100
Subject: [PATCH] [Runtime] Fix skipWakeupThreshold value
Adjust to sem_getvalue() being allowed to return 0 if there are
waiting workers.
---
emper/Runtime.hpp | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/emper/Runtime.hpp b/emper/Runtime.hpp
index f52a5843..5e417ab9 100644
--- a/emper/Runtime.hpp
+++ b/emper/Runtime.hpp
@@ -84,7 +84,14 @@ class Runtime : public Logger<LogSubsystem::RUNTI> {
// This is sound because wakeupSleepingWorkers() is called from a active
// worker which will observe its own new work in its next dispatchLoop before
// going to sleep.
- skipWakeupThreshold = -1;
+
+ // Note that sem_getvalue() is allowed to return 0 if there are
+ // waiting workers, hence we need to set the threshold also to
+ // 0. This has the disadvantage that we will perform one
+ // unnecessary sem_post. If we ever switch the wakeupSem
+ // implementation, then the skipWakeupThreshold value should be
+ // reviewed and potentially changed to '-1'.
+ skipWakeupThreshold = 0;
}
int semValue;
--
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