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-rw-r--r--sys/contrib/ck/src/ck_barrier_centralized.c59
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diff --git a/sys/contrib/ck/src/ck_barrier_centralized.c b/sys/contrib/ck/src/ck_barrier_centralized.c
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+/*
+ * Copyright 2011-2015 Samy Al Bahra.
+ * Copyright 2011 David Joseph.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <ck_barrier.h>
+#include <ck_pr.h>
+
+void
+ck_barrier_centralized(struct ck_barrier_centralized *barrier,
+ struct ck_barrier_centralized_state *state,
+ unsigned int n_threads)
+{
+ unsigned int sense, value;
+
+ /*
+ * Every execution context has a sense associated with it.
+ * This sense is reversed when the barrier is entered. Every
+ * thread will spin on the global sense until the last thread
+ * reverses it.
+ */
+ sense = state->sense = ~state->sense;
+ value = ck_pr_faa_uint(&barrier->value, 1);
+ if (value == n_threads - 1) {
+ ck_pr_store_uint(&barrier->value, 0);
+ ck_pr_fence_memory();
+ ck_pr_store_uint(&barrier->sense, sense);
+ return;
+ }
+
+ ck_pr_fence_atomic_load();
+ while (sense != ck_pr_load_uint(&barrier->sense))
+ ck_pr_stall();
+
+ ck_pr_fence_acquire();
+ return;
+}