em_chaining.h

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/*
 *   Copyright (c) 2020, Nokia Solutions and Networks
 *   All rights reserved.
 *
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 *   modification, are permitted provided that the following conditions
 *   are met:
 *
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * 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.
 *     * Neither the name of the copyright holder nor the names of its
 *       contributors may be used to endorse or promote products derived
 *       from this software without specific prior written permission.
 *
 *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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 *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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 *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
 
 /**
  * @file
  * EM event chaining support
  */
 
#ifndef EM_CHAINING_H_
#define EM_CHAINING_H_
 
#ifdef __cplusplus
extern "C" {
#endif
 
#pragma GCC visibility push(default)
/**
 * This function is declared as a weak symbol, indicating that the user should
 * override it during linking with another implementation if event chaining is
 * used.
 */
__attribute__((weak))
em_status_t event_send_device(em_event_t event, em_queue_t queue);
/**
 * This function is declared as a weak symbol, indicating that the user should
 * override it during linking with another implementation if event chaining is
 * used.
 */
__attribute__((weak))
int event_send_device_multi(const em_event_t events[], int num,
                            em_queue_t queue);
#pragma GCC visibility pop
 
/**
 * Initialize event chaining during start-up
 */
em_status_t
chaining_init(event_chaining_t *event_chaining);
 
/**
 * Terminate event chaining during shut-down
 */
em_status_t
chaining_term(const event_chaining_t *event_chaining);
 
/**
 * Send an event to out of EM (e.g. to another device) via event-chaining and a
 * user-provided function 'event_send_device()'.
 * @see event_send_device()
 */
static inline em_status_t
send_chaining(em_event_t event, em_queue_t chaining_queue)
{
        const unsigned int num_outq = em_shm->event_chaining.num_output_queues;
        const em_sched_context_type_t sched_ctx_type =
                em_locm.current.sched_context_type;
 
        if (num_outq == 0 || sched_ctx_type != EM_SCHED_CONTEXT_TYPE_ORDERED)
                return event_send_device(event, chaining_queue);
 
        /* always use the same output queue for each chaining queue */
        const internal_queue_t iq = {.queue = chaining_queue};
        em_queue_t output_queue;
        queue_elem_t *output_q_elem;
        uint32_t idx;
 
        idx = ((uint32_t)iq.device_id + (uint32_t)iq.queue_id) % num_outq;
        output_queue = em_shm->event_chaining.output_queues[idx];
        output_q_elem = queue_elem_get(output_queue);
 
        RETURN_ERROR_IF(EM_CHECK_LEVEL >= 3 && !output_q_elem,
                        EM_ERR_BAD_ID, EM_ESCOPE_EVENT_SEND_DEVICE,
                        "Invalid output queue:%" PRI_QUEUE "", output_queue);
 
        return send_output(event, output_q_elem);
}
 
/**
 * Send 'num' events out of EM (e.g. to another device) via event-chaining and a
 * user-provided function 'event_send_device_multi()'.
 * @see event_send_device_multi()
 */
static inline int
send_chaining_multi(const em_event_t events[], const int num,
                    em_queue_t chaining_queue)
{
        const unsigned int num_outq = em_shm->event_chaining.num_output_queues;
        const em_sched_context_type_t sched_ctx_type =
                em_locm.current.sched_context_type;
 
        if (num_outq == 0 || sched_ctx_type != EM_SCHED_CONTEXT_TYPE_ORDERED)
                return event_send_device_multi(events, num, chaining_queue);
 
        /* always use the same output queue for each chaining queue */
        const internal_queue_t iq = {.queue = chaining_queue};
        em_queue_t output_queue;
        queue_elem_t *output_q_elem;
        uint32_t idx;
 
        idx = ((uint32_t)iq.device_id + (uint32_t)iq.queue_id) % num_outq;
        output_queue = em_shm->event_chaining.output_queues[idx];
        output_q_elem = queue_elem_get(output_queue);
 
        if (unlikely(EM_CHECK_LEVEL >= 3 && !output_q_elem)) {
                INTERNAL_ERROR(EM_ERR_BAD_ID, EM_ESCOPE_EVENT_SEND_DEVICE_MULTI,
                               "Invalid output queue:%" PRI_QUEUE "", output_queue);
                return 0;
        }
 
        return send_output_multi(events, num, output_q_elem);
}
 
/**
 * Send an event tagged with an event group out of EM (e.g. to another device)
 * via event-chaining and a user-provided function 'event_send_device()'.
 * @see event_send_device()
 */
static inline em_status_t
send_chaining_egrp(em_event_t event, event_hdr_t *const ev_hdr,
                   em_queue_t chaining_queue,
                   const event_group_elem_t *egrp_elem)
{
        if (!egrp_elem)
                return send_chaining(event, chaining_queue);
 
        em_event_group_t save_egrp;
        event_group_elem_t *save_egrp_elem;
        int32_t save_egrp_gen;
 
        /* Send to another DEVICE with an event group */
        save_current_evgrp(&save_egrp, &save_egrp_elem, &save_egrp_gen);
        /*
         * "Simulate" a dispatch round from evgrp perspective,
         * send-device() instead of EO-receive()
         */
        event_group_set_local(ev_hdr->egrp, ev_hdr->egrp_gen, 1);
 
        em_status_t stat = send_chaining(event, chaining_queue);
 
        event_group_count_decrement(1);
        restore_current_evgrp(save_egrp, save_egrp_elem, save_egrp_gen);
 
        return stat;
}
 
/**
 * Send 'num' events tagged with an event group out of EM (e.g. to another device)
 * via event-chaining and a user-provided function 'event_send_device_multi()'.
 * @see event_send_device_multi()
 */
static inline int
send_chaining_egrp_multi(const em_event_t events[], event_hdr_t *const ev_hdrs[],
                         const int num, em_queue_t chaining_queue,
                         const event_group_elem_t *egrp_elem)
{
        if (!egrp_elem)
                return send_chaining_multi(events, num, chaining_queue);
 
        em_event_group_t save_egrp;
        event_group_elem_t *save_egrp_elem;
        int32_t save_egrp_gen;
 
        /* Send to another DEVICE with an event group */
        save_current_evgrp(&save_egrp, &save_egrp_elem, &save_egrp_gen);
        /*
         * "Simulate" dispatch rounds from evgrp perspective,
         * send-device() instead of EO-receive().
         * Decrement evgrp-count by 'num' instead of by '1'.
         * Note: event_group_set_local() called only once for
         * all events.
         */
        event_group_set_local(ev_hdrs[0]->egrp, ev_hdrs[0]->egrp_gen, num);
 
        int num_sent = send_chaining_multi(events, num, chaining_queue);
 
        event_group_count_decrement(num);
        restore_current_evgrp(save_egrp, save_egrp_elem, save_egrp_gen);
 
        return num_sent;
}
 
#ifdef __cplusplus
}
#endif
 
#endif /* EM_CHAINING_H_ */