diff options
Diffstat (limited to 'src/ck_barrier_centralized.c')
-rw-r--r-- | src/ck_barrier_centralized.c | 59 |
1 files changed, 59 insertions, 0 deletions
diff --git a/src/ck_barrier_centralized.c b/src/ck_barrier_centralized.c new file mode 100644 index 0000000..ca8cc18 --- /dev/null +++ b/src/ck_barrier_centralized.c @@ -0,0 +1,59 @@ +/* + * 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; +} |