rte_graph_model_rtc.h

/* SPDX-License-Identifier: BSD-3-Clause
 * Copyright(C) 2020 Marvell International Ltd.
 * Copyright(C) 2023 Intel Corporation
 */
 
#include "rte_graph_worker_common.h"
 
static inline void
rte_graph_walk_rtc(struct rte_graph *graph)
{
    const uint16_t nwords = graph->nb_sched_words;
    struct rte_node *node;
    uint16_t word, bit;
 
    /*
     * Nodes are assigned a bit position (sched_idx) sorted by
     * (topo_order, node_id) at graph creation time. Source nodes have
     * topo_order 0, so they always come first.
     *
     * sched_table[] maps bit positions to node offsets:
     *
     *   pending[]         sched_table[]
     *   +----------+      +------------------+
     *   | word 0   | ---> | src_node_0       | bit 0 (depth=0)
     *   | 1100...1 |      | src_node_1       | bit 1 (depth=0)
     *   |          |      | eth_input        | bit 2 (depth=1)
     *   |          |      | mpls_input       | bit 3 (depth=2)
     *   |          |      | ipv4_input       | bit 4 (depth=3)
     *   |          |      | ...              |
     *   +----------+      +------------------+
     *   | word 1   | ---> | ip4_rewrite      | bit 64 (depth=4)
     *   | ...      |      | ...              |
     *   +----------+      +------------------+
     *
     * Walk: for each word, find lowest set bit (rte_ctz64), process
     * that node, clear the bit, re-read the word (processing may
     * have set new bits), repeat.
     */
 
    /* Seed pending bitmap with source nodes */
    for (word = 0; word < nwords; word++)
        graph->pending[word] |= graph->src_pending[word];
 
    for (;;) {
        /* find first word with any pending bit */
        for (word = 0; word < nwords; word++)
            if (graph->pending[word])
                break;
        if (word == nwords)
            break; /* no more pending nodes */
 
        bit = rte_ctz64(graph->pending[word]);
        graph->pending[word] &= ~(1ULL << bit);
        node = __rte_graph_pending_node(graph, word, bit);
        __rte_node_process(graph, node);
    }
}