[dpdk-dev] [PATCH v9 08/10] eal: implement functions for thread barrier management

[Narcisa Ana Maria Vasile <navasile@linux.microsoft.com>]

From: Narcisa Vasile <navasile@microsoft.com>

Add functions for barrier init, destroy, wait.

A portable type is used to represent a barrier identifier.
The rte_thread_barrier_wait() function returns the same value
on all platforms.

Signed-off-by: Narcisa Vasile <navasile@microsoft.com>
---
 lib/eal/common/rte_thread.c  | 61 ++++++++++++++++++++++++++++++++++++
 lib/eal/include/rte_thread.h | 58 ++++++++++++++++++++++++++++++++++
 lib/eal/windows/rte_thread.c | 56 +++++++++++++++++++++++++++++++++
 3 files changed, 175 insertions(+)

diff --git a/lib/eal/common/rte_thread.c b/lib/eal/common/rte_thread.c
index 4d7d9242a9..0a9813794a 100644
--- a/lib/eal/common/rte_thread.c
+++ b/lib/eal/common/rte_thread.c
@@ -273,6 +273,67 @@ rte_thread_mutex_destroy(rte_thread_mutex_t *mutex)
 	return pthread_mutex_destroy(mutex);
 }
 
+int
+rte_thread_barrier_init(rte_thread_barrier_t *barrier, int count)
+{
+	int ret = 0;
+	pthread_barrier_t *pthread_barrier = NULL;
+
+	RTE_VERIFY(barrier != NULL);
+	RTE_VERIFY(count > 0);
+
+	pthread_barrier = calloc(1, sizeof(*pthread_barrier));
+	if (pthread_barrier == NULL) {
+		RTE_LOG(DEBUG, EAL, "Unable to initialize barrier. Insufficient memory!\n");
+		ret = ENOMEM;
+		goto cleanup;
+	}
+	ret = pthread_barrier_init(pthread_barrier, NULL, count);
+	if (ret != 0) {
+		RTE_LOG(DEBUG, EAL, "Unable to initialize barrier, ret = %d\n", ret);
+		goto cleanup;
+	}
+
+	barrier->barrier_id = pthread_barrier;
+	pthread_barrier = NULL;
+
+cleanup:
+	free(pthread_barrier);
+	return ret;
+}
+
+int rte_thread_barrier_wait(rte_thread_barrier_t *barrier)
+{
+	int ret = 0;
+
+	RTE_VERIFY(barrier != NULL);
+	RTE_VERIFY(barrier->barrier_id != NULL);
+
+	ret = pthread_barrier_wait(barrier->barrier_id);
+	if (ret == PTHREAD_BARRIER_SERIAL_THREAD) {
+		ret = RTE_THREAD_BARRIER_SERIAL_THREAD;
+	}
+
+	return ret;
+}
+
+int rte_thread_barrier_destroy(rte_thread_barrier_t *barrier)
+{
+	int ret = 0;
+
+	RTE_VERIFY(barrier != NULL);
+
+	ret = pthread_barrier_destroy(barrier->barrier_id);
+	if (ret != 0) {
+		RTE_LOG(DEBUG, EAL, "Unable to destroy barrier, ret = %d\n", ret);
+	}
+
+	free(barrier->barrier_id);
+	barrier->barrier_id = NULL;
+
+	return ret;
+}
+
 int rte_thread_cancel(rte_thread_t thread_id)
 {
 	/*
diff --git a/lib/eal/include/rte_thread.h b/lib/eal/include/rte_thread.h
index db8ef20930..b06443cf23 100644
--- a/lib/eal/include/rte_thread.h
+++ b/lib/eal/include/rte_thread.h
@@ -29,6 +29,11 @@ extern "C" {
 #include <rte_thread_types.h>
 #endif
 
+/**
+ * Returned by rte_thread_barrier_wait() when call is successful.
+ */
+#define RTE_THREAD_BARRIER_SERIAL_THREAD -1
+
 /**
  * Thread id descriptor.
  */
@@ -56,6 +61,13 @@ typedef struct {
 	rte_cpuset_t cpuset; /**< thread affinity */
 } rte_thread_attr_t;
 
+/**
+ * Thread barrier representation.
+ */
+typedef struct rte_thread_barrier_tag {
+	void* barrier_id;  /**< barrrier identifier */
+} rte_thread_barrier_t;
+
 /**
  * TLS key type, an opaque pointer.
  */
@@ -300,6 +312,52 @@ int rte_thread_mutex_unlock(rte_thread_mutex_t *mutex);
 __rte_experimental
 int rte_thread_mutex_destroy(rte_thread_mutex_t *mutex);
 
+/**
+ * Initializes a synchronization barrier.
+ *
+ * @param barrier
+ *    A pointer that references the newly created 'barrier' object.
+ *
+ * @param count
+ *    The number of threads that must enter the barrier before
+ *    the threads can continue execution.
+ *
+ * @return
+ *   On success, return 0.
+ *   On failure, return a positive errno-style error number.
+ */
+__rte_experimental
+int rte_thread_barrier_init(rte_thread_barrier_t *barrier, int count);
+
+/**
+ * Causes the calling thread to wait at the synchronization barrier 'barrier'.
+ *
+ * @param barrier
+ *    The barrier used for synchronizing the threads.
+ *
+ * @return
+ *   Return RTE_THREAD_BARRIER_SERIAL_THREAD for the thread synchronized
+ *      at the barrier.
+ *   Return 0 for all other threads.
+ *   Return a positive errno-style error number, in case of failure.
+ */
+__rte_experimental
+int rte_thread_barrier_wait(rte_thread_barrier_t *barrier);
+
+/**
+ * Releases all resources used by a synchronization barrier
+ * and uninitializes it.
+ *
+ * @param barrier
+ *    The barrier to be destroyed.
+ *
+ * @return
+ *   On success, return 0.
+ *   On failure, return a positive errno-style error number.
+ */
+__rte_experimental
+int rte_thread_barrier_destroy(rte_thread_barrier_t *barrier);
+
 /**
  * Terminates a thread.
  *
diff --git a/lib/eal/windows/rte_thread.c b/lib/eal/windows/rte_thread.c
index 239aa6be5d..2e657bbde8 100644
--- a/lib/eal/windows/rte_thread.c
+++ b/lib/eal/windows/rte_thread.c
@@ -552,6 +552,62 @@ rte_thread_mutex_destroy(rte_thread_mutex_t *mutex)
 	return 0;
 }
 
+int
+rte_thread_barrier_init(rte_thread_barrier_t *barrier, int count)
+{
+	int ret = 0;
+	SYNCHRONIZATION_BARRIER *sync_barrier = NULL;
+
+	RTE_VERIFY(barrier != NULL);
+	RTE_VERIFY(count > 0);
+
+	sync_barrier = calloc(1, sizeof(*sync_barrier));
+	if (sync_barrier == NULL) {
+		RTE_LOG(DEBUG, EAL, "Unable to initialize barrier. Insufficient memory!\n");
+		ret = ENOMEM;
+		goto cleanup;
+	}
+	if (!InitializeSynchronizationBarrier(sync_barrier, count, -1)) {
+		ret = thread_log_last_error("InitializeSynchronizationBarrier()");
+		goto cleanup;
+	}
+
+	barrier->barrier_id = sync_barrier;
+	sync_barrier = NULL;
+
+cleanup:
+	free(sync_barrier);
+	return ret;
+}
+
+int
+rte_thread_barrier_wait(rte_thread_barrier_t *barrier)
+{
+	RTE_VERIFY(barrier != NULL);
+	RTE_VERIFY(barrier->barrier_id != NULL);
+
+	if (EnterSynchronizationBarrier(barrier->barrier_id,
+				SYNCHRONIZATION_BARRIER_FLAGS_BLOCK_ONLY)) {
+
+		return RTE_THREAD_BARRIER_SERIAL_THREAD;
+	}
+
+	return 0;
+}
+
+int
+rte_thread_barrier_destroy(rte_thread_barrier_t *barrier)
+{
+	RTE_VERIFY(barrier != NULL);
+
+	DeleteSynchronizationBarrier(barrier->barrier_id);
+
+	free(barrier->barrier_id);
+	barrier->barrier_id = NULL;
+
+	return 0;
+}
+
 int
 rte_thread_cancel(rte_thread_t thread_id)
 {
-- 
2.31.0.vfs.0.1