examples/pipeline/thread.c

/* SPDX-License-Identifier: BSD-3-Clause
 * Copyright(c) 2020 Intel Corporation
 */

#include <stdlib.h>
#include <errno.h>

#include <rte_atomic.h>
#include <rte_common.h>
#include <rte_lcore.h>

#include "obj.h"
#include "thread.h"

#ifndef THREAD_PIPELINES_MAX
#define THREAD_PIPELINES_MAX                               256
#endif

#ifndef THREAD_BLOCKS_MAX
#define THREAD_BLOCKS_MAX                                  256
#endif

/* Pipeline instruction quanta: Needs to be big enough to do some meaningful
 * work, but not too big to avoid starving any other pipelines mapped to the
 * same thread. For a pipeline that executes 10 instructions per packet, a
 * quanta of 1000 instructions equates to processing 100 packets.
 */
#ifndef PIPELINE_INSTR_QUANTA
#define PIPELINE_INSTR_QUANTA                              1000
#endif

struct block {
    block_run_f block_func;
    void *block;
};

struct thread {
    struct rte_swx_pipeline *pipelines[THREAD_PIPELINES_MAX];
    struct block *blocks[THREAD_BLOCKS_MAX];
    volatile uint64_t n_pipelines;
    volatile uint64_t n_blocks;
    int enabled;
} __rte_cache_aligned;

static struct thread threads[RTE_MAX_LCORE];

int
thread_init(void)
{
    uint32_t thread_id;
    int status = 0;

    RTE_LCORE_FOREACH_WORKER(thread_id) {
        struct thread *t = &threads[thread_id];
        uint32_t i;

        t->enabled = 1;

        for (i = 0; i < THREAD_BLOCKS_MAX; i++) {
            struct block *b;

            b = calloc(1, sizeof(struct block));
            if (!b) {
                status = -ENOMEM;
                goto error;
            }

            t->blocks[i] = b;
        }
    }

    return 0;

error:
    RTE_LCORE_FOREACH_WORKER(thread_id) {
        struct thread *t = &threads[thread_id];
        uint32_t i;

        t->enabled = 0;

        for (i = 0; i < THREAD_BLOCKS_MAX; i++) {
            free(t->blocks[i]);
            t->blocks[i] = NULL;
        }
    }

    return status;
}

static uint32_t
pipeline_find(struct rte_swx_pipeline *p)
{
    uint32_t thread_id;

    for (thread_id = 0; thread_id < RTE_MAX_LCORE; thread_id++) {
        struct thread *t = &threads[thread_id];
        uint32_t i;

        if (!t->enabled)
            continue;

        for (i = 0; i < t->n_pipelines; i++)
            if (t->pipelines[i] == p)
                break;
    }

    return thread_id;
}

static uint32_t
block_find(void *b)
{
    uint32_t thread_id;

    for (thread_id = 0; thread_id < RTE_MAX_LCORE; thread_id++) {
        struct thread *t = &threads[thread_id];
        uint32_t i;

        if (!t->enabled)
            continue;

        for (i = 0; i < t->n_blocks; i++)
            if (t->blocks[i]->block == b)
                break;
    }

    return thread_id;
}

int
pipeline_enable(struct rte_swx_pipeline *p, uint32_t thread_id)
{
    struct thread *t;
    uint64_t n_pipelines;

    /* Check input params */
    if (!p || thread_id >= RTE_MAX_LCORE)
        return -EINVAL;

    if (pipeline_find(p) < RTE_MAX_LCORE)
        return -EEXIST;

    t = &threads[thread_id];
    if (!t->enabled)
        return -EINVAL;

    n_pipelines = t->n_pipelines;

    /* Check there is room for at least one more pipeline. */
    if (n_pipelines >= THREAD_PIPELINES_MAX)
        return -ENOSPC;

    /* Install the new pipeline. */
    t->pipelines[n_pipelines] = p;
    rte_wmb();
    t->n_pipelines = n_pipelines + 1;

    return 0;
}

void
pipeline_disable(struct rte_swx_pipeline *p)
{
    struct thread *t;
    uint64_t n_pipelines;
    uint32_t thread_id, i;

    /* Check input params */
    if (!p)
        return;

    /* Find the thread that runs this pipeline. */
    thread_id = pipeline_find(p);
    if (thread_id == RTE_MAX_LCORE)
        return;

    t = &threads[thread_id];
    n_pipelines = t->n_pipelines;

    for (i = 0; i < n_pipelines; i++) {
        struct rte_swx_pipeline *pipeline = t->pipelines[i];

        if (pipeline != p)
            continue;

        if (i < n_pipelines - 1) {
            struct rte_swx_pipeline *pipeline_last = t->pipelines[n_pipelines - 1];

            t->pipelines[i] = pipeline_last;
        }

        rte_wmb();
        t->n_pipelines = n_pipelines - 1;

        return;
    }

    return;
}

int
block_enable(block_run_f block_func, void *block, uint32_t thread_id)
{
    struct thread *t;
    uint64_t n_blocks;

    /* Check input params */
    if (!block_func || !block || thread_id >= RTE_MAX_LCORE)
        return -EINVAL;

    if (block_find(block) < RTE_MAX_LCORE)
        return -EEXIST;

    t = &threads[thread_id];
    if (!t->enabled)
        return -EINVAL;

    n_blocks = t->n_blocks;

    /* Check there is room for at least one more block. */
    if (n_blocks >= THREAD_BLOCKS_MAX)
        return -ENOSPC;

    /* Install the new block. */
    t->blocks[n_blocks]->block_func = block_func;
    t->blocks[n_blocks]->block = block;

    rte_wmb();
    t->n_blocks = n_blocks + 1;

    return 0;
}

void
block_disable(void *block)
{
    struct thread *t;
    uint64_t n_blocks;
    uint32_t thread_id, i;

    /* Check input params */
    if (!block)
        return;

    /* Find the thread that runs this block. */
    thread_id = block_find(block);
    if (thread_id == RTE_MAX_LCORE)
        return;

    t = &threads[thread_id];
    n_blocks = t->n_blocks;

    for (i = 0; i < n_blocks; i++) {
        struct block *b = t->blocks[i];

        if (block != b->block)
            continue;

        if (i < n_blocks - 1) {
            struct block *block_last = t->blocks[n_blocks - 1];

            t->blocks[i] = block_last;
        }

        rte_wmb();
        t->n_blocks = n_blocks - 1;

        rte_wmb();
        t->blocks[n_blocks - 1] = b;

        return;
    }
}

int
thread_main(void *arg __rte_unused)
{
    struct thread *t;
    uint32_t thread_id;

    thread_id = rte_lcore_id();
    t = &threads[thread_id];

    /* Dispatch loop. */
    for ( ; ; ) {
        uint32_t i;

        /* Pipelines. */
        for (i = 0; i < t->n_pipelines; i++)
            rte_swx_pipeline_run(t->pipelines[i], PIPELINE_INSTR_QUANTA);

        /* Blocks. */
        for (i = 0; i < t->n_blocks; i++) {
            struct block *b = t->blocks[i];

            b->block_func(b->block);
        }
    }

    return 0;
}