DPDK  16.11.9
performance-thread/common/lthread_sched.c
/*-
* BSD LICENSE
*
* Copyright(c) 2015 Intel Corporation. All rights reserved.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* 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 Intel Corporation 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
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/*
* Some portions of this software is derived from the
* https://github.com/halayli/lthread which carrys the following license.
*
* Copyright (C) 2012, Hasan Alayli <halayli@gmail.com>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. 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.
*
* THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#define RTE_MEM 1
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdint.h>
#include <stddef.h>
#include <limits.h>
#include <inttypes.h>
#include <unistd.h>
#include <pthread.h>
#include <fcntl.h>
#include <sys/time.h>
#include <sys/mman.h>
#include <sched.h>
#include <rte_prefetch.h>
#include <rte_per_lcore.h>
#include <rte_atomic.h>
#include <rte_atomic_64.h>
#include <rte_log.h>
#include <rte_common.h>
#include "lthread_api.h"
#include "lthread_int.h"
#include "lthread_sched.h"
#include "lthread_objcache.h"
#include "lthread_timer.h"
#include "lthread_mutex.h"
#include "lthread_cond.h"
#include "lthread_tls.h"
#include "lthread_diag.h"
/*
* This file implements the lthread scheduler
* The scheduler is the function lthread_run()
* This must be run as the main loop of an EAL thread.
*
* Currently once a scheduler is created it cannot be destroyed
* When a scheduler shuts down it is assumed that the application is terminating
*/
static rte_atomic16_t num_schedulers;
static rte_atomic16_t active_schedulers;
/* one scheduler per lcore */
RTE_DEFINE_PER_LCORE(struct lthread_sched *, this_sched) = NULL;
struct lthread_sched *schedcore[LTHREAD_MAX_LCORES];
diag_callback diag_cb;
uint64_t diag_mask;
/* constructor */
void lthread_sched_ctor(void) __attribute__ ((constructor));
void lthread_sched_ctor(void)
{
memset(schedcore, 0, sizeof(schedcore));
rte_atomic16_init(&num_schedulers);
rte_atomic16_set(&num_schedulers, 1);
rte_atomic16_init(&active_schedulers);
rte_atomic16_set(&active_schedulers, 0);
diag_cb = NULL;
}
enum sched_alloc_phase {
SCHED_ALLOC_OK,
SCHED_ALLOC_QNODE_POOL,
SCHED_ALLOC_READY_QUEUE,
SCHED_ALLOC_PREADY_QUEUE,
SCHED_ALLOC_LTHREAD_CACHE,
SCHED_ALLOC_STACK_CACHE,
SCHED_ALLOC_PERLT_CACHE,
SCHED_ALLOC_TLS_CACHE,
SCHED_ALLOC_COND_CACHE,
SCHED_ALLOC_MUTEX_CACHE,
};
static int
_lthread_sched_alloc_resources(struct lthread_sched *new_sched)
{
int alloc_status;
do {
/* Initialize per scheduler queue node pool */
alloc_status = SCHED_ALLOC_QNODE_POOL;
new_sched->qnode_pool =
_qnode_pool_create("qnode pool", LTHREAD_PREALLOC);
if (new_sched->qnode_pool == NULL)
break;
/* Initialize per scheduler local ready queue */
alloc_status = SCHED_ALLOC_READY_QUEUE;
new_sched->ready = _lthread_queue_create("ready queue");
if (new_sched->ready == NULL)
break;
/* Initialize per scheduler local peer ready queue */
alloc_status = SCHED_ALLOC_PREADY_QUEUE;
new_sched->pready = _lthread_queue_create("pready queue");
if (new_sched->pready == NULL)
break;
/* Initialize per scheduler local free lthread cache */
alloc_status = SCHED_ALLOC_LTHREAD_CACHE;
new_sched->lthread_cache =
_lthread_objcache_create("lthread cache",
sizeof(struct lthread),
LTHREAD_PREALLOC);
if (new_sched->lthread_cache == NULL)
break;
/* Initialize per scheduler local free stack cache */
alloc_status = SCHED_ALLOC_STACK_CACHE;
new_sched->stack_cache =
_lthread_objcache_create("stack_cache",
sizeof(struct lthread_stack),
LTHREAD_PREALLOC);
if (new_sched->stack_cache == NULL)
break;
/* Initialize per scheduler local free per lthread data cache */
alloc_status = SCHED_ALLOC_PERLT_CACHE;
new_sched->per_lthread_cache =
_lthread_objcache_create("per_lt cache",
RTE_PER_LTHREAD_SECTION_SIZE,
LTHREAD_PREALLOC);
if (new_sched->per_lthread_cache == NULL)
break;
/* Initialize per scheduler local free tls cache */
alloc_status = SCHED_ALLOC_TLS_CACHE;
new_sched->tls_cache =
_lthread_objcache_create("TLS cache",
sizeof(struct lthread_tls),
LTHREAD_PREALLOC);
if (new_sched->tls_cache == NULL)
break;
/* Initialize per scheduler local free cond var cache */
alloc_status = SCHED_ALLOC_COND_CACHE;
new_sched->cond_cache =
_lthread_objcache_create("cond cache",
sizeof(struct lthread_cond),
LTHREAD_PREALLOC);
if (new_sched->cond_cache == NULL)
break;
/* Initialize per scheduler local free mutex cache */
alloc_status = SCHED_ALLOC_MUTEX_CACHE;
new_sched->mutex_cache =
_lthread_objcache_create("mutex cache",
sizeof(struct lthread_mutex),
LTHREAD_PREALLOC);
if (new_sched->mutex_cache == NULL)
break;
alloc_status = SCHED_ALLOC_OK;
} while (0);
/* roll back on any failure */
switch (alloc_status) {
case SCHED_ALLOC_MUTEX_CACHE:
_lthread_objcache_destroy(new_sched->cond_cache);
/* fall through */
case SCHED_ALLOC_COND_CACHE:
_lthread_objcache_destroy(new_sched->tls_cache);
/* fall through */
case SCHED_ALLOC_TLS_CACHE:
_lthread_objcache_destroy(new_sched->per_lthread_cache);
/* fall through */
case SCHED_ALLOC_PERLT_CACHE:
_lthread_objcache_destroy(new_sched->stack_cache);
/* fall through */
case SCHED_ALLOC_STACK_CACHE:
_lthread_objcache_destroy(new_sched->lthread_cache);
/* fall through */
case SCHED_ALLOC_LTHREAD_CACHE:
_lthread_queue_destroy(new_sched->pready);
/* fall through */
case SCHED_ALLOC_PREADY_QUEUE:
_lthread_queue_destroy(new_sched->ready);
/* fall through */
case SCHED_ALLOC_READY_QUEUE:
_qnode_pool_destroy(new_sched->qnode_pool);
/* fall through */
case SCHED_ALLOC_QNODE_POOL:
/* fall through */
case SCHED_ALLOC_OK:
break;
}
return alloc_status;
}
/*
* Create a scheduler on the current lcore
*/
struct lthread_sched *_lthread_sched_create(size_t stack_size)
{
int status;
struct lthread_sched *new_sched;
unsigned lcoreid = rte_lcore_id();
RTE_ASSERT(stack_size <= LTHREAD_MAX_STACK_SIZE);
if (stack_size == 0)
stack_size = LTHREAD_MAX_STACK_SIZE;
new_sched =
rte_calloc_socket(NULL, 1, sizeof(struct lthread_sched),
RTE_CACHE_LINE_SIZE,
if (new_sched == NULL) {
RTE_LOG(CRIT, LTHREAD,
"Failed to allocate memory for scheduler\n");
return NULL;
}
_lthread_key_pool_init();
new_sched->stack_size = stack_size;
new_sched->birth = rte_rdtsc();
THIS_SCHED = new_sched;
status = _lthread_sched_alloc_resources(new_sched);
if (status != SCHED_ALLOC_OK) {
RTE_LOG(CRIT, LTHREAD,
"Failed to allocate resources for scheduler code = %d\n",
status);
rte_free(new_sched);
return NULL;
}
bzero(&new_sched->ctx, sizeof(struct ctx));
new_sched->lcore_id = lcoreid;
schedcore[lcoreid] = new_sched;
new_sched->run_flag = 1;
DIAG_EVENT(new_sched, LT_DIAG_SCHED_CREATE, rte_lcore_id(), 0);
return new_sched;
}
/*
* Set the number of schedulers in the system
*/
int lthread_num_schedulers_set(int num)
{
rte_atomic16_set(&num_schedulers, num);
return (int)rte_atomic16_read(&num_schedulers);
}
/*
* Return the number of schedulers active
*/
int lthread_active_schedulers(void)
{
return (int)rte_atomic16_read(&active_schedulers);
}
void lthread_scheduler_shutdown(unsigned lcoreid)
{
uint64_t coreid = (uint64_t) lcoreid;
if (coreid < LTHREAD_MAX_LCORES) {
if (schedcore[coreid] != NULL)
schedcore[coreid]->run_flag = 0;
}
}
void lthread_scheduler_shutdown_all(void)
{
uint64_t i;
/*
* give time for all schedulers to have started
* Note we use sched_yield() rather than pthread_yield() to allow
* for the possibility of a pthread wrapper on lthread_yield(),
* something that is not possible unless the scheduler is running.
*/
while (rte_atomic16_read(&active_schedulers) <
rte_atomic16_read(&num_schedulers))
sched_yield();
for (i = 0; i < LTHREAD_MAX_LCORES; i++) {
if (schedcore[i] != NULL)
schedcore[i]->run_flag = 0;
}
}
/*
* Resume a suspended lthread
*/
static inline void
_lthread_resume(struct lthread *lt) __attribute__ ((always_inline));
static inline void _lthread_resume(struct lthread *lt)
{
struct lthread_sched *sched = THIS_SCHED;
struct lthread_stack *s;
uint64_t state = lt->state;
#if LTHREAD_DIAG
int init = 0;
#endif
sched->current_lthread = lt;
if (state & (BIT(ST_LT_CANCELLED) | BIT(ST_LT_EXITED))) {
/* if detached we can free the thread now */
if (state & BIT(ST_LT_DETACH)) {
_lthread_free(lt);
sched->current_lthread = NULL;
return;
}
}
if (state & BIT(ST_LT_INIT)) {
/* first time this thread has been run */
/* assign thread to this scheduler */
lt->sched = THIS_SCHED;
/* allocate stack */
s = _stack_alloc();
lt->stack_container = s;
_lthread_set_stack(lt, s->stack, s->stack_size);
/* allocate memory for TLS used by this thread */
_lthread_tls_alloc(lt);
lt->state = BIT(ST_LT_READY);
#if LTHREAD_DIAG
init = 1;
#endif
}
DIAG_EVENT(lt, LT_DIAG_LTHREAD_RESUMED, init, lt);
/* switch to the new thread */
ctx_switch(&lt->ctx, &sched->ctx);
/* If posting to a queue that could be read by another lcore
* we defer the queue write till now to ensure the context has been
* saved before the other core tries to resume it
* This applies to blocking on mutex, cond, and to set_affinity
*/
if (lt->pending_wr_queue != NULL) {
struct lthread_queue *dest = lt->pending_wr_queue;
lt->pending_wr_queue = NULL;
/* queue the current thread to the specified queue */
_lthread_queue_insert_mp(dest, lt);
}
sched->current_lthread = NULL;
}
/*
* Handle sleep timer expiry
*/
void
_sched_timer_cb(struct rte_timer *tim, void *arg)
{
struct lthread *lt = (struct lthread *) arg;
uint64_t state = lt->state;
DIAG_EVENT(lt, LT_DIAG_LTHREAD_TMR_EXPIRED, &lt->tim, 0);
if (lt->state & BIT(ST_LT_CANCELLED))
(THIS_SCHED)->nb_blocked_threads--;
lt->state = state | BIT(ST_LT_EXPIRED);
_lthread_resume(lt);
lt->state = state & CLEARBIT(ST_LT_EXPIRED);
}
/*
* Returns 0 if there is a pending job in scheduler or 1 if done and can exit.
*/
static inline int _lthread_sched_isdone(struct lthread_sched *sched)
{
return (sched->run_flag == 0) &&
(_lthread_queue_empty(sched->ready)) &&
(_lthread_queue_empty(sched->pready)) &&
(sched->nb_blocked_threads == 0);
}
/*
* Wait for all schedulers to start
*/
static inline void _lthread_schedulers_sync_start(void)
{
rte_atomic16_inc(&active_schedulers);
/* wait for lthread schedulers
* Note we use sched_yield() rather than pthread_yield() to allow
* for the possibility of a pthread wrapper on lthread_yield(),
* something that is not possible unless the scheduler is running.
*/
while (rte_atomic16_read(&active_schedulers) <
rte_atomic16_read(&num_schedulers))
sched_yield();
}
/*
* Wait for all schedulers to stop
*/
static inline void _lthread_schedulers_sync_stop(void)
{
rte_atomic16_dec(&active_schedulers);
rte_atomic16_dec(&num_schedulers);
/* wait for schedulers
* Note we use sched_yield() rather than pthread_yield() to allow
* for the possibility of a pthread wrapper on lthread_yield(),
* something that is not possible unless the scheduler is running.
*/
while (rte_atomic16_read(&active_schedulers) > 0)
sched_yield();
}
/*
* Run the lthread scheduler
* This loop is the heart of the system
*/
void lthread_run(void)
{
struct lthread_sched *sched = THIS_SCHED;
struct lthread *lt = NULL;
RTE_LOG(INFO, LTHREAD,
"starting scheduler %p on lcore %u phys core %u\n",
sched, rte_lcore_id(),
/* if more than one, wait for all schedulers to start */
_lthread_schedulers_sync_start();
/*
* This is the main scheduling loop
* So long as there are tasks in existence we run this loop.
* We check for:-
* expired timers,
* the local ready queue,
* and the peer ready queue,
*
* and resume lthreads ad infinitum.
*/
while (!_lthread_sched_isdone(sched)) {
lt = _lthread_queue_poll(sched->ready);
if (lt != NULL)
_lthread_resume(lt);
lt = _lthread_queue_poll(sched->pready);
if (lt != NULL)
_lthread_resume(lt);
}
/* if more than one wait for all schedulers to stop */
_lthread_schedulers_sync_stop();
(THIS_SCHED) = NULL;
RTE_LOG(INFO, LTHREAD,
"stopping scheduler %p on lcore %u phys core %u\n",
sched, rte_lcore_id(),
fflush(stdout);
}
/*
* Return the scheduler for this lcore
*
*/
struct lthread_sched *_lthread_sched_get(unsigned int lcore_id)
{
struct lthread_sched *res = NULL;
if (lcore_id < LTHREAD_MAX_LCORES)
res = schedcore[lcore_id];
return res;
}
/*
* migrate the current thread to another scheduler running
* on the specified lcore.
*/
int lthread_set_affinity(unsigned lcoreid)
{
struct lthread *lt = THIS_LTHREAD;
struct lthread_sched *dest_sched;
if (unlikely(lcoreid >= LTHREAD_MAX_LCORES))
return POSIX_ERRNO(EINVAL);
DIAG_EVENT(lt, LT_DIAG_LTHREAD_AFFINITY, lcoreid, 0);
dest_sched = schedcore[lcoreid];
if (unlikely(dest_sched == NULL))
return POSIX_ERRNO(EINVAL);
if (likely(dest_sched != THIS_SCHED)) {
lt->sched = dest_sched;
lt->pending_wr_queue = dest_sched->pready;
_affinitize();
return 0;
}
return 0;
}