[RFC, v1 4/6] graph: enhance graph walk by cross-core dispatch

[Zhirun Yan]

This patch enhance the task scheduler mechanism to enable dispatching
tasks to another worker cores. Currently, there is only a local work
queue for one graph to walk. We introduce a scheduler worker queue in
each worker core for dispatching tasks. It will perform the walk on
scheduler work queue first, then handle the local work queue.

Signed-off-by: Haiyue Wang <haiyue.wang at intel.com>
Signed-off-by: Cunming Liang <cunming.liang at intel.com>
Signed-off-by: Zhirun Yan <zhirun.yan at intel.com>
---
 lib/graph/graph.c            |  6 ++++++
 lib/graph/rte_graph_worker.h | 11 +++++++++++
 2 files changed, 17 insertions(+)

diff --git a/lib/graph/graph.c b/lib/graph/graph.c
index b4eb18175a..49ea2b3fbb 100644
--- a/lib/graph/graph.c
+++ b/lib/graph/graph.c
@@ -368,6 +368,8 @@ rte_graph_destroy(rte_graph_t id)
 	while (graph != NULL) {
 		tmp = STAILQ_NEXT(graph, next);
 		if (graph->id == id) {
+			/* Destroy the schedule work queue if has */
+			graph_sched_wq_destroy(graph);
 			/* Call fini() of the all the nodes in the graph */
 			graph_node_fini(graph);
 			/* Destroy graph fast path memory */
@@ -470,6 +472,10 @@ graph_clone(struct graph *parent_graph, const char *name,
 	if (graph_node_init(graph))
 		goto graph_mem_destroy;
 
+	/* Create the graph schedule work queue */
+	if (graph_sched_wq_create(graph, parent_graph))
+		goto graph_mem_destroy;
+
 	/* All good, Lets add the graph to the list */
 	graph_id++;
 	STAILQ_INSERT_TAIL(&graph_list, graph, next);
diff --git a/lib/graph/rte_graph_worker.h b/lib/graph/rte_graph_worker.h
index faf3f31ddc..e98697d880 100644
--- a/lib/graph/rte_graph_worker.h
+++ b/lib/graph/rte_graph_worker.h
@@ -177,6 +177,7 @@ static inline void
 rte_graph_walk(struct rte_graph *graph)
 {
 	const rte_graph_off_t *cir_start = graph->cir_start;
+	const unsigned int lcore_id = graph->lcore_id;
 	const rte_node_t mask = graph->cir_mask;
 	uint32_t head = graph->head;
 	struct rte_node *node;
@@ -184,6 +185,9 @@ rte_graph_walk(struct rte_graph *graph)
 	uint16_t rc;
 	void **objs;
 
+	if (graph->wq != NULL)
+		__rte_graph_sched_wq_process(graph);
+
 	/*
 	 * Walk on the source node(s) ((cir_start - head) -> cir_start) and then
 	 * on the pending streams (cir_start -> (cir_start + mask) -> cir_start)
@@ -205,6 +209,12 @@ rte_graph_walk(struct rte_graph *graph)
 		objs = node->objs;
 		rte_prefetch0(objs);
 
+		/* Schedule the node until all task/objs are done */
+		if (node->lcore_id != RTE_MAX_LCORE && (int32_t)head > 0 &&
+		    lcore_id != node->lcore_id && graph->rq != NULL &&
+		    __rte_graph_sched_node_enqueue(node, graph->rq))
+			goto next;
+
 		if (rte_graph_has_stats_feature()) {
 			start = rte_rdtsc();
 			rc = node->process(graph, node, objs, node->idx);
@@ -215,6 +225,7 @@ rte_graph_walk(struct rte_graph *graph)
 			node->process(graph, node, objs, node->idx);
 		}
 		node->idx = 0;
+	next:
 		head = likely((int32_t)head > 0) ? head & mask : head;
 	}
 	graph->tail = 0;
-- 
2.25.1