threads.h

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/*
 * Copyright (c) 2015 Cisco and/or its affiliates.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at:
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
#ifndef included_vlib_threads_h
#define included_vlib_threads_h
 
#include <vlib/main.h>
#include <vppinfra/callback.h>
#include <linux/sched.h>
 
void vlib_set_thread_name (char *name);
 
/* arg is actually a vlib__thread_t * */
typedef void (vlib_thread_function_t) (void *arg);
 
typedef struct vlib_thread_registration_
{
  /* constructor generated list of thread registrations */
  struct vlib_thread_registration_ *next;
 
  /* config parameters */
  char *name;
  char *short_name;
  vlib_thread_function_t *function;
  uword mheap_size;
  int fixed_count;
  u32 count;
  int no_data_structure_clone;
  u32 frame_queue_nelts;
 
  /* All threads of this type run on pthreads */
  int use_pthreads;
  u32 first_index;
  uword *coremask;
} vlib_thread_registration_t;
 
/*
 * Frames have their cpu / vlib_main_t index in the low-order N bits
 * Make VLIB_MAX_CPUS a power-of-two, please...
 */
 
#ifndef VLIB_MAX_CPUS
#define VLIB_MAX_CPUS 256
#endif
 
#if VLIB_MAX_CPUS > CLIB_MAX_MHEAPS
#error Please increase number of per-cpu mheaps
#endif
 
#define VLIB_CPU_MASK (VLIB_MAX_CPUS - 1)       /* 0x3f, max */
#define VLIB_OFFSET_MASK (~VLIB_CPU_MASK)
 
#define VLIB_LOG2_THREAD_STACK_SIZE (21)
#define VLIB_THREAD_STACK_SIZE (1<<VLIB_LOG2_THREAD_STACK_SIZE)
 
typedef enum
{
  VLIB_FRAME_QUEUE_ELT_DISPATCH_FRAME,
} vlib_frame_queue_msg_type_t;
 
typedef struct
{
  CLIB_CACHE_LINE_ALIGN_MARK (cacheline0);
  volatile u32 valid;
  u32 msg_type;
  u32 n_vectors;
  u32 last_n_vectors;
 
  /* 256 * 4 = 1024 bytes, even mult of cache line size */
  u32 buffer_index[VLIB_FRAME_SIZE];
}
vlib_frame_queue_elt_t;
 
typedef struct
{
  /* First cache line */
  CLIB_CACHE_LINE_ALIGN_MARK (cacheline0);
  volatile u32 *wait_at_barrier;
  volatile u32 *workers_at_barrier;
 
  /* Second Cache Line */
    CLIB_CACHE_LINE_ALIGN_MARK (cacheline1);
  void *thread_mheap;
  u8 *thread_stack;
  void (*thread_function) (void *);
  void *thread_function_arg;
  i64 recursion_level;
  elog_track_t elog_track;
  u32 instance_id;
  vlib_thread_registration_t *registration;
  u8 *name;
  u64 barrier_sync_count;
  u8 barrier_elog_enabled;
  const char *barrier_caller;
  const char *barrier_context;
  volatile u32 *node_reforks_required;
 
  long lwp;
  int cpu_id;
  int core_id;
  int numa_id;
  pthread_t thread_id;
} vlib_worker_thread_t;
 
extern vlib_worker_thread_t *vlib_worker_threads;
 
typedef struct
{
  /* enqueue side */
  CLIB_CACHE_LINE_ALIGN_MARK (cacheline0);
  volatile u64 tail;
  u32 enqueue_full_events;
 
  /* dequeue side */
    CLIB_CACHE_LINE_ALIGN_MARK (cacheline1);
  volatile u64 head;
  u64 trace;
  u64 vector_threshold;
 
  /* dequeue hint to enqueue side */
    CLIB_CACHE_LINE_ALIGN_MARK (cacheline2);
  volatile u64 head_hint;
 
  /* read-only, constant, shared */
    CLIB_CACHE_LINE_ALIGN_MARK (cacheline3);
  vlib_frame_queue_elt_t *elts;
  u32 nelts;
}
vlib_frame_queue_t;
 
typedef struct
{
  vlib_frame_queue_elt_t **handoff_queue_elt_by_thread_index;
  vlib_frame_queue_t **congested_handoff_queue_by_thread_index;
} vlib_frame_queue_per_thread_data_t;
 
typedef struct
{
  u32 node_index;
  u32 frame_queue_nelts;
  u32 queue_hi_thresh;
 
  vlib_frame_queue_t **vlib_frame_queues;
  vlib_frame_queue_per_thread_data_t *per_thread_data;
 
  /* for frame queue tracing */
  frame_queue_trace_t *frame_queue_traces;
  frame_queue_nelt_counter_t *frame_queue_histogram;
} vlib_frame_queue_main_t;
 
typedef struct
{
  uword node_index;
  uword type_opaque;
  uword data;
} vlib_process_signal_event_mt_args_t;
 
/* Called early, in thread 0's context */
clib_error_t *vlib_thread_init (vlib_main_t * vm);
 
int vlib_frame_queue_enqueue (vlib_main_t * vm, u32 node_runtime_index,
                              u32 frame_queue_index, vlib_frame_t * frame,
                              vlib_frame_queue_msg_type_t type);
 
void vlib_worker_thread_node_runtime_update (void);
 
void vlib_create_worker_threads (vlib_main_t * vm, int n,
                                 void (*thread_function) (void *));
 
void vlib_worker_thread_init (vlib_worker_thread_t * w);
u32 vlib_frame_queue_main_init (u32 node_index, u32 frame_queue_nelts);
 
/* Check for a barrier sync request every 30ms */
#define BARRIER_SYNC_DELAY (0.030000)
 
#if CLIB_DEBUG > 0
/* long barrier timeout, for gdb... */
#define BARRIER_SYNC_TIMEOUT (600.1)
#else
#define BARRIER_SYNC_TIMEOUT (1.0)
#endif
 
#define vlib_worker_thread_barrier_sync(X) {vlib_worker_thread_barrier_sync_int(X, __FUNCTION__);}
 
void vlib_worker_thread_barrier_sync_int (vlib_main_t * vm,
                                          const char *func_name);
void vlib_worker_thread_barrier_release (vlib_main_t * vm);
u8 vlib_worker_thread_barrier_held (void);
void vlib_worker_thread_initial_barrier_sync_and_release (vlib_main_t * vm);
void vlib_worker_thread_node_refork (void);
/**
 * Wait until each of the workers has been once around the track
 */
void vlib_worker_wait_one_loop (void);
 
static_always_inline uword
vlib_get_thread_index (void)
{
  return __os_thread_index;
}
 
always_inline void
vlib_smp_unsafe_warning (void)
{
  if (CLIB_DEBUG > 0)
    {
      if (vlib_get_thread_index ())
        fformat (stderr, "%s: SMP unsafe warning...\n", __FUNCTION__);
    }
}
 
always_inline int
__foreach_vlib_main_helper (vlib_main_t *ii, vlib_main_t **p)
{
  vlib_main_t *vm;
  u32 index = ii - (vlib_main_t *) 0;
 
  if (index >= vec_len (vlib_global_main.vlib_mains))
    return 0;
 
  *p = vm = vlib_global_main.vlib_mains[index];
  ASSERT (index == 0 || vm->parked_at_barrier == 1);
  return 1;
}
 
#define foreach_vlib_main()                                                   \
  for (vlib_main_t *ii = 0, *this_vlib_main;                                  \
       __foreach_vlib_main_helper (ii, &this_vlib_main); ii++)                \
    if (this_vlib_main)
 
#define foreach_sched_policy \
  _(SCHED_OTHER, OTHER, "other") \
  _(SCHED_BATCH, BATCH, "batch") \
  _(SCHED_IDLE, IDLE, "idle")   \
  _(SCHED_FIFO, FIFO, "fifo")   \
  _(SCHED_RR, RR, "rr")
 
typedef enum
{
#define _(v,f,s) SCHED_POLICY_##f = v,
  foreach_sched_policy
#undef _
    SCHED_POLICY_N,
} sched_policy_t;
 
typedef struct
{
  clib_error_t *(*vlib_launch_thread_cb) (void *fp, vlib_worker_thread_t * w,
                                          unsigned cpu_id);
  clib_error_t *(*vlib_thread_set_lcore_cb) (u32 thread, u16 cpu);
} vlib_thread_callbacks_t;
 
typedef struct
{
  /* Link list of registrations, built by constructors */
  vlib_thread_registration_t *next;
 
  /* Vector of registrations, w/ non-data-structure clones at the top */
  vlib_thread_registration_t **registrations;
 
  uword *thread_registrations_by_name;
 
  vlib_worker_thread_t *worker_threads;
 
  /*
   * Launch all threads as pthreads,
   * not eal_rte_launch (strict affinity) threads
   */
  int use_pthreads;
 
  /* Number of vlib_main / vnet_main clones */
  u32 n_vlib_mains;
 
  /* Number of thread stacks to create */
  u32 n_thread_stacks;
 
  /* Number of pthreads */
  u32 n_pthreads;
 
  /* Number of threads */
  u32 n_threads;
 
  /* Number of cores to skip, must match the core mask */
  u32 skip_cores;
 
  /* Thread prefix name */
  u8 *thread_prefix;
 
  /* main thread lcore */
  u32 main_lcore;
 
  /* Bitmap of available CPU cores */
  uword *cpu_core_bitmap;
 
  /* Bitmap of available CPU sockets (NUMA nodes) */
  uword *cpu_socket_bitmap;
 
  /* Worker handoff queues */
  vlib_frame_queue_main_t *frame_queue_mains;
 
  /* worker thread initialization barrier */
  volatile u32 worker_thread_release;
 
  /* scheduling policy */
  u32 sched_policy;
 
  /* scheduling policy priority */
  u32 sched_priority;
 
  /* callbacks */
  vlib_thread_callbacks_t cb;
  int extern_thread_mgmt;
 
  /* NUMA-bound heap size */
  uword numa_heap_size;
 
} vlib_thread_main_t;
 
extern vlib_thread_main_t vlib_thread_main;
 
#include <vlib/global_funcs.h>
 
#define VLIB_REGISTER_THREAD(x,...)                     \
  __VA_ARGS__ vlib_thread_registration_t x;             \
static void __vlib_add_thread_registration_##x (void)   \
  __attribute__((__constructor__)) ;                    \
static void __vlib_add_thread_registration_##x (void)   \
{                                                       \
  vlib_thread_main_t * tm = &vlib_thread_main;          \
  x.next = tm->next;                                    \
  tm->next = &x;                                        \
}                                                       \
static void __vlib_rm_thread_registration_##x (void)    \
  __attribute__((__destructor__)) ;                     \
static void __vlib_rm_thread_registration_##x (void)    \
{                                                       \
  vlib_thread_main_t * tm = &vlib_thread_main;          \
  VLIB_REMOVE_FROM_LINKED_LIST (tm->next, &x, next);    \
}                                                       \
__VA_ARGS__ vlib_thread_registration_t x
 
always_inline u32
vlib_num_workers ()
{
  return vlib_thread_main.n_vlib_mains - 1;
}
 
always_inline u32
vlib_get_worker_thread_index (u32 worker_index)
{
  return worker_index + 1;
}
 
always_inline u32
vlib_get_worker_index (u32 thread_index)
{
  return thread_index - 1;
}
 
always_inline u32
vlib_get_current_worker_index ()
{
  return vlib_get_thread_index () - 1;
}
 
static inline void
vlib_worker_thread_barrier_check (void)
{
  if (PREDICT_FALSE (*vlib_worker_threads->wait_at_barrier))
    {
      vlib_global_main_t *vgm = vlib_get_global_main ();
      vlib_main_t *vm = vlib_get_main ();
      u32 thread_index = vm->thread_index;
      f64 t = vlib_time_now (vm);
 
      if (PREDICT_FALSE (vec_len (vm->barrier_perf_callbacks) != 0))
        clib_call_callbacks (vm->barrier_perf_callbacks, vm,
                             vm->clib_time.last_cpu_time, 0 /* enter */ );
 
      if (PREDICT_FALSE (vlib_worker_threads->barrier_elog_enabled))
        {
          vlib_worker_thread_t *w = vlib_worker_threads + thread_index;
          /* *INDENT-OFF* */
          ELOG_TYPE_DECLARE (e) = {
            .format = "barrier-wait-thread-%d",
            .format_args = "i4",
          };
          /* *INDENT-ON* */
 
          struct
          {
            u32 thread_index;
          } __clib_packed *ed;
 
          ed = ELOG_TRACK_DATA (&vlib_global_main.elog_main, e, w->elog_track);
          ed->thread_index = thread_index;
        }
 
      if (CLIB_DEBUG > 0)
        {
          vm = vlib_get_main ();
          vm->parked_at_barrier = 1;
        }
      clib_atomic_fetch_add (vlib_worker_threads->workers_at_barrier, 1);
      while (*vlib_worker_threads->wait_at_barrier)
        ;
 
      /*
       * Recompute the offset from thread-0 time.
       * Note that vlib_time_now adds vm->time_offset, so
       * clear it first. Save the resulting idea of "now", to
       * see how well we're doing. See show_clock_command_fn(...)
       */
      {
        f64 now;
        vm->time_offset = 0.0;
        now = vlib_time_now (vm);
        vm->time_offset = vgm->vlib_mains[0]->time_last_barrier_release - now;
        vm->time_last_barrier_release = vlib_time_now (vm);
      }
 
      if (CLIB_DEBUG > 0)
        vm->parked_at_barrier = 0;
      clib_atomic_fetch_add (vlib_worker_threads->workers_at_barrier, -1);
 
      if (PREDICT_FALSE (*vlib_worker_threads->node_reforks_required))
        {
          if (PREDICT_FALSE (vlib_worker_threads->barrier_elog_enabled))
            {
              t = vlib_time_now (vm) - t;
              vlib_worker_thread_t *w = vlib_worker_threads + thread_index;
              /* *INDENT-OFF* */
              ELOG_TYPE_DECLARE (e) = {
                .format = "barrier-refork-thread-%d",
                .format_args = "i4",
              };
              /* *INDENT-ON* */
 
              struct
              {
                u32 thread_index;
              } __clib_packed *ed;
 
              ed = ELOG_TRACK_DATA (&vlib_global_main.elog_main, e,
                                    w->elog_track);
              ed->thread_index = thread_index;
            }
 
          vlib_worker_thread_node_refork ();
          clib_atomic_fetch_add (vlib_worker_threads->node_reforks_required,
                                 -1);
          while (*vlib_worker_threads->node_reforks_required)
            ;
        }
      if (PREDICT_FALSE (vlib_worker_threads->barrier_elog_enabled))
        {
          t = vlib_time_now (vm) - t;
          vlib_worker_thread_t *w = vlib_worker_threads + thread_index;
          /* *INDENT-OFF* */
          ELOG_TYPE_DECLARE (e) = {
            .format = "barrier-released-thread-%d: %dus",
            .format_args = "i4i4",
          };
          /* *INDENT-ON* */
 
          struct
          {
            u32 thread_index;
            u32 duration;
          } __clib_packed *ed;
 
          ed = ELOG_TRACK_DATA (&vlib_global_main.elog_main, e, w->elog_track);
          ed->thread_index = thread_index;
          ed->duration = (int) (1000000.0 * t);
        }
 
      if (PREDICT_FALSE (vec_len (vm->barrier_perf_callbacks) != 0))
        clib_call_callbacks (vm->barrier_perf_callbacks, vm,
                             vm->clib_time.last_cpu_time, 1 /* leave */ );
    }
}
 
always_inline vlib_main_t *
vlib_get_worker_vlib_main (u32 worker_index)
{
  vlib_main_t *vm;
  vlib_thread_main_t *tm = &vlib_thread_main;
  ASSERT (worker_index < tm->n_vlib_mains - 1);
  vm = vlib_get_main_by_index (worker_index + 1);
  ASSERT (vm);
  return vm;
}
 
static inline u8
vlib_thread_is_main_w_barrier (void)
{
  return (!vlib_num_workers ()
          || ((vlib_get_thread_index () == 0
               && vlib_worker_threads->wait_at_barrier[0])));
}
 
static inline void
vlib_put_frame_queue_elt (vlib_frame_queue_elt_t * hf)
{
  CLIB_MEMORY_BARRIER ();
  hf->valid = 1;
}
 
static inline vlib_frame_queue_elt_t *
vlib_get_frame_queue_elt (u32 frame_queue_index, u32 index)
{
  vlib_frame_queue_t *fq;
  vlib_frame_queue_elt_t *elt;
  vlib_thread_main_t *tm = &vlib_thread_main;
  vlib_frame_queue_main_t *fqm =
    vec_elt_at_index (tm->frame_queue_mains, frame_queue_index);
  u64 new_tail;
 
  fq = fqm->vlib_frame_queues[index];
  ASSERT (fq);
 
  new_tail = clib_atomic_add_fetch (&fq->tail, 1);
 
  /* Wait until a ring slot is available */
  while (new_tail >= fq->head_hint + fq->nelts)
    vlib_worker_thread_barrier_check ();
 
  elt = fq->elts + (new_tail & (fq->nelts - 1));
 
  /* this would be very bad... */
  while (elt->valid)
    ;
 
  elt->msg_type = VLIB_FRAME_QUEUE_ELT_DISPATCH_FRAME;
  elt->last_n_vectors = elt->n_vectors = 0;
 
  return elt;
}
 
static inline vlib_frame_queue_t *
is_vlib_frame_queue_congested (u32 frame_queue_index,
                               u32 index,
                               u32 queue_hi_thresh,
                               vlib_frame_queue_t **
                               handoff_queue_by_worker_index)
{
  vlib_frame_queue_t *fq;
  vlib_thread_main_t *tm = &vlib_thread_main;
  vlib_frame_queue_main_t *fqm =
    vec_elt_at_index (tm->frame_queue_mains, frame_queue_index);
 
  fq = handoff_queue_by_worker_index[index];
  if (fq != (vlib_frame_queue_t *) (~0))
    return fq;
 
  fq = fqm->vlib_frame_queues[index];
  ASSERT (fq);
 
  if (PREDICT_FALSE (fq->tail >= (fq->head_hint + queue_hi_thresh)))
    {
      /* a valid entry in the array will indicate the queue has reached
       * the specified threshold and is congested
       */
      handoff_queue_by_worker_index[index] = fq;
      fq->enqueue_full_events++;
      return fq;
    }
 
  return NULL;
}
 
static inline vlib_frame_queue_elt_t *
vlib_get_worker_handoff_queue_elt (u32 frame_queue_index,
                                   u32 vlib_worker_index,
                                   vlib_frame_queue_elt_t **
                                   handoff_queue_elt_by_worker_index)
{
  vlib_frame_queue_elt_t *elt;
 
  if (handoff_queue_elt_by_worker_index[vlib_worker_index])
    return handoff_queue_elt_by_worker_index[vlib_worker_index];
 
  elt = vlib_get_frame_queue_elt (frame_queue_index, vlib_worker_index);
 
  handoff_queue_elt_by_worker_index[vlib_worker_index] = elt;
 
  return elt;
}
 
u8 *vlib_thread_stack_init (uword thread_index);
int vlib_thread_cb_register (struct vlib_main_t *vm,
                             vlib_thread_callbacks_t * cb);
extern void *rpc_call_main_thread_cb_fn;
 
void
vlib_process_signal_event_mt_helper (vlib_process_signal_event_mt_args_t *
                                     args);
void vlib_rpc_call_main_thread (void *function, u8 * args, u32 size);
void vlib_get_thread_core_numa (vlib_worker_thread_t * w, unsigned cpu_id);
vlib_thread_main_t *vlib_get_thread_main_not_inline (void);
 
#endif /* included_vlib_threads_h */
 
/*
 * fd.io coding-style-patch-verification: ON
 *
 * Local Variables:
 * eval: (c-set-style "gnu")
 * End:
 */