main.c

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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.
 */
/*
 * main.c: main vector processing loop
 *
 * Copyright (c) 2008 Eliot Dresselhaus
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 *  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 *  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 *  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
 *  LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 *  OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 *  WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

#include <math.h>
#include <vppinfra/format.h>
#include <vlib/vlib.h>
#include <vlib/threads.h>

#include <vlib/unix/cj.h>

CJ_GLOBAL_LOG_PROTOTYPE;

/* Actually allocate a few extra slots of vector data to support
   speculative vector enqueues which overflow vector data in next frame. */
#define VLIB_FRAME_SIZE_ALLOC (VLIB_FRAME_SIZE + 4)

always_inline u32
vlib_frame_bytes (u32 n_scalar_bytes, u32 n_vector_bytes)
{
  u32 n_bytes;

  /* Make room for vlib_frame_t plus scalar arguments. */
  n_bytes = vlib_frame_vector_byte_offset (n_scalar_bytes);

  /* Make room for vector arguments.
     Allocate a few extra slots of vector data to support
     speculative vector enqueues which overflow vector data in next frame. */
#define VLIB_FRAME_SIZE_EXTRA 4
  n_bytes += (VLIB_FRAME_SIZE + VLIB_FRAME_SIZE_EXTRA) * n_vector_bytes;

  /* Magic number is first 32bit number after vector data.
     Used to make sure that vector data is never overrun. */
#define VLIB_FRAME_MAGIC (0xabadc0ed)
  n_bytes += sizeof (u32);

  /* Pad to cache line. */
  n_bytes = round_pow2 (n_bytes, CLIB_CACHE_LINE_BYTES);

  return n_bytes;
}

always_inline u32 *
vlib_frame_find_magic (vlib_frame_t * f, vlib_node_t * node)
{
  void * p = f;

  p += vlib_frame_vector_byte_offset (node->scalar_size);

  p += (VLIB_FRAME_SIZE + VLIB_FRAME_SIZE_EXTRA) * node->vector_size;

  return p;
}

static vlib_frame_size_t *
get_frame_size_info (vlib_node_main_t * nm,
                     u32 n_scalar_bytes, u32 n_vector_bytes)
{
  uword key = (n_scalar_bytes << 16) | n_vector_bytes;
  uword * p, i;

  p = hash_get (nm->frame_size_hash, key);
  if (p)
    i = p[0];
  else
    {
      i = vec_len (nm->frame_sizes);
      vec_validate (nm->frame_sizes, i);
      hash_set (nm->frame_size_hash, key, i);
    }

  return vec_elt_at_index (nm->frame_sizes, i);
}

static u32
vlib_frame_alloc_to_node (vlib_main_t * vm, u32 to_node_index, u32 frame_flags)
{
  vlib_node_main_t * nm = &vm->node_main;
  vlib_frame_size_t * fs;
  vlib_node_t * to_node;
  vlib_frame_t * f;
  u32 fi, l, n, scalar_size, vector_size;

  to_node = vlib_get_node (vm, to_node_index);

  scalar_size = to_node->scalar_size;
  vector_size = to_node->vector_size;

  fs = get_frame_size_info (nm, scalar_size, vector_size);
  n = vlib_frame_bytes (scalar_size, vector_size);
  if ((l = vec_len (fs->free_frame_indices)) > 0)
    {
      /* Allocate from end of free list. */
      fi = fs->free_frame_indices[l - 1];
      f = vlib_get_frame_no_check (vm, fi);
      _vec_len (fs->free_frame_indices) = l - 1;
    }
  else
    {
      f = clib_mem_alloc_aligned_no_fail (n, VLIB_FRAME_ALIGN);
      f->cpu_index = vm->cpu_index;
      fi = vlib_frame_index_no_check (vm, f);
    }

  /* Poison frame when debugging. */
  if (CLIB_DEBUG > 0)
    {
      u32 save_cpu_index = f->cpu_index;

      memset (f, 0xfe, n);

      f->cpu_index = save_cpu_index;
    }

  /* Insert magic number. */
  {
    u32 * magic;

    magic = vlib_frame_find_magic (f, to_node);
    *magic = VLIB_FRAME_MAGIC;
  }

  f->flags = VLIB_FRAME_IS_ALLOCATED | frame_flags;
  f->n_vectors = 0;
  f->scalar_size = scalar_size;
  f->vector_size = vector_size;

  fs->n_alloc_frames += 1;

  return fi;
}

/* Allocate a frame for from FROM_NODE to TO_NODE via TO_NEXT_INDEX.
   Returns frame index. */
static u32
vlib_frame_alloc (vlib_main_t * vm, vlib_node_runtime_t * from_node_runtime, u32 to_next_index)
{
  vlib_node_t * from_node;

  from_node = vlib_get_node (vm, from_node_runtime->node_index);
  ASSERT (to_next_index < vec_len (from_node->next_nodes));

  return vlib_frame_alloc_to_node (vm,
                                   from_node->next_nodes[to_next_index],
                                   /* frame_flags */ 0);
}

vlib_frame_t *
vlib_get_frame_to_node (vlib_main_t * vm, u32 to_node_index)
{
  u32 fi = vlib_frame_alloc_to_node (vm, to_node_index,
                                     /* frame_flags */ VLIB_FRAME_FREE_AFTER_DISPATCH);
  return vlib_get_frame (vm, fi);
}

void vlib_put_frame_to_node (vlib_main_t * vm, u32 to_node_index, vlib_frame_t * f)
{
  vlib_pending_frame_t * p;
  vlib_node_t * to_node;

  if (f->n_vectors == 0)
    return;

  to_node = vlib_get_node (vm, to_node_index);

  vec_add2 (vm->node_main.pending_frames, p, 1);

  f->flags |= VLIB_FRAME_PENDING;
  p->frame_index = vlib_frame_index (vm, f);
  p->node_runtime_index = to_node->runtime_index;
  p->next_frame_index = VLIB_PENDING_FRAME_NO_NEXT_FRAME;
}

/* Free given frame. */
void
vlib_frame_free (vlib_main_t * vm,
                 vlib_node_runtime_t * r,
                 vlib_frame_t * f)
{
  vlib_node_main_t * nm = &vm->node_main;
  vlib_node_t * node;
  vlib_frame_size_t * fs;
  u32 frame_index;
  
  ASSERT (f->flags & VLIB_FRAME_IS_ALLOCATED);

  node = vlib_get_node (vm, r->node_index);
  fs = get_frame_size_info (nm, node->scalar_size, node->vector_size);

  frame_index = vlib_frame_index (vm, f);

  ASSERT (f->flags & VLIB_FRAME_IS_ALLOCATED);

  /* No next frames may point to freed frame. */
  if (CLIB_DEBUG > 0)
    {
      vlib_next_frame_t * nf;
      vec_foreach (nf, vm->node_main.next_frames)
        ASSERT (nf->frame_index != frame_index);
    }

  f->flags &= ~VLIB_FRAME_IS_ALLOCATED;

  vec_add1 (fs->free_frame_indices, frame_index);
  ASSERT (fs->n_alloc_frames > 0);
  fs->n_alloc_frames -= 1;
}

static clib_error_t *
show_frame_stats (vlib_main_t * vm,
                  unformat_input_t * input,
                  vlib_cli_command_t * cmd)
{
  vlib_node_main_t * nm = &vm->node_main;
  vlib_frame_size_t * fs;
  
  vlib_cli_output (vm, "%=6s%=12s%=12s", "Size", "# Alloc", "# Free");
  vec_foreach (fs, nm->frame_sizes)
    {
      u32 n_alloc = fs->n_alloc_frames;
      u32 n_free = vec_len (fs->free_frame_indices);

      if (n_alloc + n_free > 0)
        vlib_cli_output (vm, "%=6d%=12d%=12d",
                         fs - nm->frame_sizes, n_alloc, n_free);
    }

  return 0;
}

VLIB_CLI_COMMAND (show_frame_stats_cli, static) = {
  .path = "show vlib frame-allocation",
  .short_help = "Show node dispatch frame statistics",
  .function = show_frame_stats,
};

/* Change ownership of enqueue rights to given next node. */
static void
vlib_next_frame_change_ownership (vlib_main_t * vm,
                                  vlib_node_runtime_t * node_runtime,
                                  u32 next_index)
{
  vlib_node_main_t * nm = &vm->node_main;
  vlib_next_frame_t * next_frame;
  vlib_node_t * node, * next_node;

  node = vec_elt (nm->nodes, node_runtime->node_index);

  /* Only internal & input nodes are allowed to call other nodes. */
  ASSERT (node->type == VLIB_NODE_TYPE_INTERNAL
          || node->type == VLIB_NODE_TYPE_INPUT
          || node->type == VLIB_NODE_TYPE_PROCESS);

  ASSERT (vec_len (node->next_nodes) == node_runtime->n_next_nodes);

  next_frame = vlib_node_runtime_get_next_frame (vm, node_runtime, next_index);
  next_node = vec_elt (nm->nodes, node->next_nodes[next_index]);

  if (next_node->owner_node_index != VLIB_INVALID_NODE_INDEX)
    {
      /* Get frame from previous owner. */
      vlib_next_frame_t * owner_next_frame;
      vlib_next_frame_t tmp;

      owner_next_frame =
        vlib_node_get_next_frame (vm,
                                  next_node->owner_node_index,
                                  next_node->owner_next_index);

      /* Swap target next frame with owner's. */
      tmp = owner_next_frame[0];
      owner_next_frame[0] = next_frame[0];
      next_frame[0] = tmp;

      /*
       * If next_frame is already pending, we have to track down
       * all pending frames and fix their next_frame_index fields.
       */
      if (next_frame->flags & VLIB_FRAME_PENDING)
        {
          vlib_pending_frame_t * p;
          if (next_frame->frame_index != ~0)
            {
              vec_foreach (p, nm->pending_frames)
                {
                  if (p->frame_index == next_frame->frame_index)
                    {
                      p->next_frame_index = 
                        next_frame - vm->node_main.next_frames;
                    }
                }
            }
        }
    }
  else
    {
      /* No previous owner. Take ownership. */
      next_frame->flags |= VLIB_FRAME_OWNER;
    }
                                           
  /* Record new owner. */
  next_node->owner_node_index = node->index;
  next_node->owner_next_index = next_index;

  /* Now we should be owner. */
  ASSERT (next_frame->flags & VLIB_FRAME_OWNER);
}             

/* Make sure that magic number is still there.
   Otherwise, it is likely that caller has overrun frame arguments. */
always_inline void
validate_frame_magic (vlib_main_t * vm,
                      vlib_frame_t * f,
                      vlib_node_t * n,
                      uword next_index)
{
  vlib_node_t * next_node = vlib_get_node (vm, n->next_nodes[next_index]);
  u32 * magic = vlib_frame_find_magic (f, next_node);
  ASSERT (VLIB_FRAME_MAGIC == magic[0]);
}

vlib_frame_t *
vlib_get_next_frame_internal (vlib_main_t * vm,
                              vlib_node_runtime_t * node,
                              u32 next_index,
                              u32 allocate_new_next_frame)
{
  vlib_frame_t * f;
  vlib_next_frame_t * nf;
  u32 n_used;

  nf = vlib_node_runtime_get_next_frame (vm, node, next_index);

  /* Make sure this next frame owns right to enqueue to destination frame. */
  if (PREDICT_FALSE (! (nf->flags & VLIB_FRAME_OWNER)))
    vlib_next_frame_change_ownership (vm, node, next_index);

  /* ??? Don't need valid flag: can use frame_index == ~0 */
  if (PREDICT_FALSE (! (nf->flags & VLIB_FRAME_IS_ALLOCATED)))
    {
      nf->frame_index = vlib_frame_alloc (vm, node, next_index);
      nf->flags |= VLIB_FRAME_IS_ALLOCATED;
    }

  f = vlib_get_frame (vm, nf->frame_index);

  /* Has frame been removed from pending vector (e.g. finished dispatching)?
     If so we can reuse frame. */
  if ((nf->flags & VLIB_FRAME_PENDING) && ! (f->flags & VLIB_FRAME_PENDING))
    {
      nf->flags &= ~VLIB_FRAME_PENDING;
      f->n_vectors = 0;
    }

  /* Allocate new frame if current one is already full. */
  n_used = f->n_vectors;
  if (n_used >= VLIB_FRAME_SIZE || (allocate_new_next_frame && n_used > 0))
    {
      /* Old frame may need to be freed after dispatch, since we'll have
         two redundant frames from node -> next node. */
      if (! (nf->flags & VLIB_FRAME_NO_FREE_AFTER_DISPATCH))
        {
          vlib_frame_t * f_old = vlib_get_frame (vm, nf->frame_index);
          f_old->flags |= VLIB_FRAME_FREE_AFTER_DISPATCH;
        }

      /* Allocate new frame to replace full one. */
      nf->frame_index = vlib_frame_alloc (vm, node, next_index);
      f = vlib_get_frame (vm, nf->frame_index);
      n_used = f->n_vectors;
    }

  /* Should have free vectors in frame now. */
  ASSERT (n_used < VLIB_FRAME_SIZE);

  if (CLIB_DEBUG > 0)
    {
      validate_frame_magic (vm, f,
                            vlib_get_node (vm, node->node_index),
                            next_index);
    }

  return f;
}

static void
vlib_put_next_frame_validate (vlib_main_t * vm,
                              vlib_node_runtime_t * rt,
                              u32 next_index,
                              u32 n_vectors_left)
{
  vlib_node_main_t * nm = &vm->node_main;
  vlib_next_frame_t * nf;
  vlib_frame_t * f;
  vlib_node_runtime_t * next_rt;
  vlib_node_t * next_node;
  u32 n_before, n_after;

  nf = vlib_node_runtime_get_next_frame (vm, rt, next_index);
  f = vlib_get_frame (vm, nf->frame_index);

  ASSERT (n_vectors_left <= VLIB_FRAME_SIZE);
  n_after = VLIB_FRAME_SIZE - n_vectors_left;
  n_before = f->n_vectors;

  ASSERT (n_after >= n_before);

  next_rt = vec_elt_at_index (nm->nodes_by_type[VLIB_NODE_TYPE_INTERNAL],
                              nf->node_runtime_index);
  next_node = vlib_get_node (vm, next_rt->node_index);
  if (n_after > 0 && next_node->validate_frame)
    {
      u8 * msg = next_node->validate_frame (vm, rt, f);
      if (msg)
        {
          clib_warning ("%v", msg);
          ASSERT (0);
        }
      vec_free (msg);
    }
}

void
vlib_put_next_frame (vlib_main_t * vm,
                     vlib_node_runtime_t * r,
                     u32 next_index,
                     u32 n_vectors_left)
{
  vlib_node_main_t * nm = &vm->node_main;
  vlib_next_frame_t * nf;
  vlib_frame_t * f;
  u32 n_vectors_in_frame;

  if (DPDK == 0 && CLIB_DEBUG > 0)
    vlib_put_next_frame_validate (vm, r, next_index, n_vectors_left);

  nf = vlib_node_runtime_get_next_frame (vm, r, next_index);
  f = vlib_get_frame (vm, nf->frame_index);

  /* Make sure that magic number is still there.  Otherwise, caller
     has overrun frame meta data. */
  if (CLIB_DEBUG > 0)
    {
      vlib_node_t * node = vlib_get_node (vm, r->node_index);
      validate_frame_magic (vm, f, node, next_index);
    }

  /* Convert # of vectors left -> number of vectors there. */
  ASSERT (n_vectors_left <= VLIB_FRAME_SIZE);
  n_vectors_in_frame = VLIB_FRAME_SIZE - n_vectors_left;

  f->n_vectors = n_vectors_in_frame;

  /* If vectors were added to frame, add to pending vector. */
  if (PREDICT_TRUE (n_vectors_in_frame > 0))
    {
      vlib_pending_frame_t * p;
      u32 v0, v1;
      
      r->cached_next_index = next_index;

      if (!(f->flags & VLIB_FRAME_PENDING))
        {
          __attribute__((unused)) vlib_node_t *node;
          vlib_node_t *next_node;
          vlib_node_runtime_t *next_runtime;

          node = vlib_get_node (vm, r->node_index);
          next_node = vlib_get_next_node (vm, r->node_index, next_index);
          next_runtime = vlib_node_get_runtime (vm, next_node->index);

          vec_add2 (nm->pending_frames, p, 1);

          p->frame_index = nf->frame_index;
          p->node_runtime_index = nf->node_runtime_index;
          p->next_frame_index = nf - nm->next_frames;
          nf->flags |= VLIB_FRAME_PENDING;
          f->flags |= VLIB_FRAME_PENDING;

          /* 
           * If we're going to dispatch this frame on another thread,
           * force allocation of a new frame. Otherwise, we create
           * a dangling frame reference. Each thread has its own copy of
           * the next_frames vector.
           */
          if (0 && r->cpu_index != next_runtime->cpu_index)
            {
              nf->frame_index = ~0;
              nf->flags &= ~(VLIB_FRAME_PENDING | VLIB_FRAME_IS_ALLOCATED);
            }
        }

      /* Copy trace flag from next_frame and from runtime. */
      nf->flags |= (nf->flags & VLIB_NODE_FLAG_TRACE) | (r->flags & VLIB_NODE_FLAG_TRACE);

      v0 = nf->vectors_since_last_overflow;
      v1 = v0 + n_vectors_in_frame;
      nf->vectors_since_last_overflow = v1;
      if (PREDICT_FALSE (v1 < v0))
        {
          vlib_node_t * node = vlib_get_node (vm, r->node_index);
          vec_elt (node->n_vectors_by_next_node, next_index) += v0;
        }
    }
}

/* Sync up runtime (32 bit counters) and main node stats (64 bit counters). */
never_inline void
vlib_node_runtime_sync_stats (vlib_main_t * vm,
                              vlib_node_runtime_t * r,
                              uword n_calls,
                              uword n_vectors,
                              uword n_clocks)
{
  vlib_node_t * n = vlib_get_node (vm, r->node_index);

  n->stats_total.calls += n_calls + r->calls_since_last_overflow;
  n->stats_total.vectors += n_vectors + r->vectors_since_last_overflow;
  n->stats_total.clocks += n_clocks + r->clocks_since_last_overflow;
  n->stats_total.max_clock = r->max_clock;
  n->stats_total.max_clock_n = r->max_clock_n;

  r->calls_since_last_overflow = 0;
  r->vectors_since_last_overflow = 0;
  r->clocks_since_last_overflow = 0;
}

always_inline void __attribute__((unused))
vlib_process_sync_stats (vlib_main_t * vm,
                         vlib_process_t * p,
                         uword n_calls,
                         uword n_vectors,
                         uword n_clocks)
{
  vlib_node_runtime_t * rt = &p->node_runtime;
  vlib_node_t * n = vlib_get_node (vm, rt->node_index);
  vlib_node_runtime_sync_stats (vm, rt, n_calls, n_vectors, n_clocks);
  n->stats_total.suspends += p->n_suspends;
  p->n_suspends = 0;
}

void vlib_node_sync_stats (vlib_main_t * vm, vlib_node_t * n)
{
  vlib_node_runtime_t * rt;

  if (n->type == VLIB_NODE_TYPE_PROCESS)
    {
      /* Nothing to do for PROCESS nodes except in main thread */
      if (vm != &vlib_global_main) return;

      vlib_process_t * p = vlib_get_process_from_node (vm, n);
      n->stats_total.suspends += p->n_suspends;
      p->n_suspends = 0;
      rt = &p->node_runtime;
    }
  else
    rt = vec_elt_at_index (vm->node_main.nodes_by_type[n->type], n->runtime_index);

  vlib_node_runtime_sync_stats (vm, rt, 0, 0, 0);

  /* Sync up runtime next frame vector counters with main node structure. */
  {
    vlib_next_frame_t * nf;
    uword i;
    for (i = 0; i < rt->n_next_nodes; i++)
      {
        nf = vlib_node_runtime_get_next_frame (vm, rt, i);
        vec_elt (n->n_vectors_by_next_node, i) += nf->vectors_since_last_overflow;
        nf->vectors_since_last_overflow = 0;
      }
  }
}

always_inline u32
vlib_node_runtime_update_stats (vlib_main_t * vm,
                                vlib_node_runtime_t * node,
                                uword n_calls,
                                uword n_vectors,
                                uword n_clocks)
{
  u32 ca0, ca1, v0, v1, cl0, cl1, r;

  cl0 = cl1 = node->clocks_since_last_overflow;
  ca0 = ca1 = node->calls_since_last_overflow;
  v0 = v1 = node->vectors_since_last_overflow;

  ca1 = ca0 + n_calls;
  v1 = v0 + n_vectors;
  cl1 = cl0 + n_clocks;

  node->calls_since_last_overflow = ca1;
  node->clocks_since_last_overflow = cl1;
  node->vectors_since_last_overflow = v1;
  node->max_clock_n = node->max_clock > n_clocks ?
                      node->max_clock_n : n_vectors;
  node->max_clock = node->max_clock > n_clocks ?
                    node->max_clock : n_clocks;

  r = vlib_node_runtime_update_main_loop_vector_stats (vm, node, n_vectors);

  if (PREDICT_FALSE (ca1 < ca0 || v1 < v0 || cl1 < cl0))
    {
      node->calls_since_last_overflow = ca0;
      node->clocks_since_last_overflow = cl0;
      node->vectors_since_last_overflow = v0;
      vlib_node_runtime_sync_stats (vm, node, n_calls, n_vectors, n_clocks);
    }

  return r;
}

always_inline void
vlib_process_update_stats (vlib_main_t * vm,
                           vlib_process_t * p,
                           uword n_calls,
                           uword n_vectors,
                           uword n_clocks)
{
  vlib_node_runtime_update_stats (vm, &p->node_runtime,
                                  n_calls, n_vectors, n_clocks);
}

static clib_error_t *
vlib_cli_elog_clear (vlib_main_t * vm,
                     unformat_input_t * input,
                     vlib_cli_command_t * cmd)
{
  elog_reset_buffer (&vm->elog_main);
  return 0;
}

VLIB_CLI_COMMAND (elog_clear_cli, static) = {
  .path = "event-logger clear",
  .short_help = "Clear the event log",
  .function = vlib_cli_elog_clear,
};

#ifdef CLIB_UNIX
static clib_error_t *
elog_save_buffer (vlib_main_t * vm,
                  unformat_input_t * input,
                  vlib_cli_command_t * cmd)
{
  elog_main_t * em = &vm->elog_main;
  char * file, * chroot_file;
  clib_error_t * error = 0;

  if (! unformat (input, "%s", &file))
    {
      vlib_cli_output (vm, "expected file name, got `%U'",
                       format_unformat_error, input);
      return 0;
    }

  /* It's fairly hard to get "../oopsie" through unformat; just in case */
  if (strstr(file, "..") || index(file, '/'))
    {
      vlib_cli_output (vm, "illegal characters in filename '%s'", file);
      return 0;
    }

  chroot_file = (char *) format (0, "/tmp/%s%c", file, 0);

  vec_free(file);

  vlib_cli_output (vm, "Saving %wd of %wd events to %s",
                   elog_n_events_in_buffer (em),
                   elog_buffer_capacity (em),
                   chroot_file);
  
  vlib_worker_thread_barrier_sync (vm);
  error =  elog_write_file (em, chroot_file);
  vlib_worker_thread_barrier_release(vm);
  vec_free (chroot_file);
  return error;
}

VLIB_CLI_COMMAND (elog_save_cli, static) = {
  .path = "event-logger save",
  .short_help = "event-logger save <filename> (saves log in /tmp/<filename>)",
  .function = elog_save_buffer,
};

static clib_error_t *
elog_stop (vlib_main_t * vm,
           unformat_input_t * input,
           vlib_cli_command_t * cmd)
{
  elog_main_t * em = &vm->elog_main;

  em->n_total_events_disable_limit = em->n_total_events;

  vlib_cli_output (vm, "Stopped the event logger...");
  return 0;
}

VLIB_CLI_COMMAND (elog_stop_cli, static) = {
  .path = "event-logger stop",
  .short_help = "Stop the event-logger",
  .function = elog_stop,
};

static clib_error_t *
elog_restart (vlib_main_t * vm,
            unformat_input_t * input,
            vlib_cli_command_t * cmd)
{
  elog_main_t * em = &vm->elog_main;

  em->n_total_events_disable_limit = ~0;

  vlib_cli_output (vm, "Restarted the event logger...");
  return 0;
}

VLIB_CLI_COMMAND (elog_restart_cli, static) = {
  .path = "event-logger restart",
  .short_help = "Restart the event-logger",
  .function = elog_restart,
};

static clib_error_t *
elog_resize (vlib_main_t * vm,
             unformat_input_t * input,
             vlib_cli_command_t * cmd)
{
  elog_main_t * em = &vm->elog_main;
  u32 tmp;

  /* Stop the parade */
  elog_reset_buffer (&vm->elog_main);

  if (unformat (input, "%d", &tmp))
    {
      elog_alloc (em, tmp);
      em->n_total_events_disable_limit = ~0;
    }
  else 
    return clib_error_return (0, "Must specify how many events in the ring");

  vlib_cli_output (vm, "Resized ring and restarted the event logger...");
  return 0;
}

VLIB_CLI_COMMAND (elog_resize_cli, static) = {
  .path = "event-logger resize",
  .short_help = "event-logger resize <nnn>",
  .function = elog_resize,
};

#endif /* CLIB_UNIX */

static void elog_show_buffer_internal (vlib_main_t * vm, u32 n_events_to_show)
{
  elog_main_t * em = &vm->elog_main;
  elog_event_t * e, * es;
  f64 dt;

  /* Show events in VLIB time since log clock starts after VLIB clock. */
  dt = (em->init_time.cpu - vm->clib_time.init_cpu_time) 
    * vm->clib_time.seconds_per_clock;

  es = elog_peek_events (em);
  vlib_cli_output (vm, "%d of %d events in buffer, logger %s", vec_len (es), 
                   em->event_ring_size,
                   em->n_total_events < em->n_total_events_disable_limit ?
                   "running" : "stopped");
  vec_foreach (e, es)
    {
      vlib_cli_output (vm, "%18.9f: %U",
                       e->time + dt,
                       format_elog_event, em, e);
      n_events_to_show--;
      if (n_events_to_show == 0)
        break;
    }
  vec_free (es);
  
}

static clib_error_t *
elog_show_buffer (vlib_main_t * vm,
                  unformat_input_t * input,
                  vlib_cli_command_t * cmd)
{
  u32 n_events_to_show;
  clib_error_t * error = 0;

  n_events_to_show = 250;
  while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
    {
      if (unformat (input, "%d", &n_events_to_show))
        ;
      else if (unformat (input, "all"))
        n_events_to_show = ~0;
      else
        return unformat_parse_error (input);
    }
  elog_show_buffer_internal (vm, n_events_to_show);
  return error;
}

VLIB_CLI_COMMAND (elog_show_cli, static) = {
  .path = "show event-logger",
  .short_help = "Show event logger info",
  .function = elog_show_buffer,
};

void vlib_gdb_show_event_log (void)
{
  elog_show_buffer_internal (vlib_get_main(), (u32)~0);
}

static inline void
vlib_elog_main_loop_event (vlib_main_t * vm,
                           u32 node_index,
                           u64 time,
                           u32 n_vectors,
                           u32 is_return)
{
  vlib_main_t * evm = &vlib_global_main;
  elog_main_t * em = &evm->elog_main;

  if (VLIB_ELOG_MAIN_LOOP && n_vectors)
    elog_track (em,
          /* event type */
          vec_elt_at_index (is_return
                            ? evm->node_return_elog_event_types
                            : evm->node_call_elog_event_types,
                            node_index),
          /* track */
          (vm->cpu_index ? &vlib_worker_threads[vm->cpu_index].elog_track :
           &em->default_track),
          /* data to log */ n_vectors);
}

void vlib_dump_context_trace (vlib_main_t *vm, u32 bi)
{
  vlib_node_main_t * vnm = &vm->node_main;
  vlib_buffer_t * b;
  u8 i, n;

  if (VLIB_BUFFER_TRACE_TRAJECTORY)
    {
      b = vlib_get_buffer (vm, bi);
      n = b->pre_data[0];

      fformat(stderr, "Context trace for bi %d b 0x%llx, visited %d\n",
              bi, b, n);

      if (n == 0 || n > 20)
        {
          fformat(stderr, "n is unreasonable\n");
          return;
        }


      for (i = 0; i < n; i++)
        {
          u32 node_index;

          node_index = b->pre_data[i+1];

          if (node_index > vec_len (vnm->nodes))
            {
              fformat(stderr, "Skip bogus node index %d\n", node_index);
              continue;
            }
      
          fformat(stderr, "%v (%d)\n", vnm->nodes[node_index]->name, 
                  node_index);
        }
    }
  else
    {
      fformat(stderr, 
              "in vlib/buffers.h, #define VLIB_BUFFER_TRACE_TRAJECTORY 1\n");
    }
}


/* static_always_inline */ u64
dispatch_node (vlib_main_t * vm,
               vlib_node_runtime_t * node,
               vlib_node_type_t type,
               vlib_node_state_t dispatch_state,
               vlib_frame_t * frame,
               u64 last_time_stamp)
{
  uword n, v;
  u64 t;
  vlib_node_main_t * nm = &vm->node_main;
  vlib_next_frame_t * nf;

  if (CLIB_DEBUG > 0)
    {
      vlib_node_t * n = vlib_get_node (vm, node->node_index);
      ASSERT (n->type == type);
    }

  /* Only non-internal nodes may be disabled. */
  if (type != VLIB_NODE_TYPE_INTERNAL && node->state != dispatch_state)
    {
      ASSERT (type != VLIB_NODE_TYPE_INTERNAL);
      return last_time_stamp;
    }

  if ((type == VLIB_NODE_TYPE_PRE_INPUT || type == VLIB_NODE_TYPE_INPUT)
      && dispatch_state != VLIB_NODE_STATE_INTERRUPT)
    {
      u32 c = node->input_main_loops_per_call;
      /* Only call node when count reaches zero. */
      if (c)
        {
          node->input_main_loops_per_call = c - 1;
          return last_time_stamp;
        }
    }

  /* Speculatively prefetch next frames. */
  if (node->n_next_nodes > 0)
    {
      nf = vec_elt_at_index (nm->next_frames, node->next_frame_index);
      CLIB_PREFETCH (nf, 4 * sizeof (nf[0]), WRITE);
    }

  vm->cpu_time_last_node_dispatch = last_time_stamp;

  if (1  /* || vm->cpu_index == node->cpu_index */)
    {
      vlib_main_t *stat_vm;

      stat_vm = /* vlib_mains ? vlib_mains[0] : */ vm;

      vlib_elog_main_loop_event (vm, node->node_index,
                                 last_time_stamp,
                                 frame ? frame->n_vectors : 0,
                                 /* is_after */ 0);
      
      /*
       * Turn this on if you run into
       * "bad monkey" contexts, and you want to know exactly
       * which nodes they've visited... See ixge.c...
       */
      if (VLIB_BUFFER_TRACE_TRAJECTORY && frame)
        {
          int i;
          int log_index;
          u32 * from;
          from = vlib_frame_vector_args (frame);
          for (i = 0; i < frame->n_vectors; i++)
            {
              vlib_buffer_t *b = vlib_get_buffer (vm, from[i]);
              ASSERT (b->pre_data[0] < 32);
              log_index = b->pre_data[0]++ + 1;
              b->pre_data[log_index] = node->node_index;
            }
          n = node->function (vm, node, frame);
        }
      else
          n = node->function (vm, node, frame);

      t = clib_cpu_time_now ();

      vlib_elog_main_loop_event (vm, node->node_index, t, n, /* is_after */ 1);

      vm->main_loop_vectors_processed += n;
      vm->main_loop_nodes_processed += n > 0;

      v = vlib_node_runtime_update_stats (stat_vm, node,
                                          /* n_calls */ 1,
                                          /* n_vectors */ n,
                                          /* n_clocks */ t - last_time_stamp);

      /* When in interrupt mode and vector rate crosses threshold switch to
         polling mode. */
      if ((DPDK == 0 && dispatch_state == VLIB_NODE_STATE_INTERRUPT)
          || (DPDK == 0 && dispatch_state == VLIB_NODE_STATE_POLLING
              && (node->flags 
                  & VLIB_NODE_FLAG_SWITCH_FROM_INTERRUPT_TO_POLLING_MODE)))
        {
          ELOG_TYPE_DECLARE (e) = {
            .function = (char *) __FUNCTION__,
            .format = "%s vector length %d, switching to %s",
            .format_args = "T4i4t4",
            .n_enum_strings = 2,
            .enum_strings = {
              "interrupt", "polling",
            },
          };
          struct { u32 node_name, vector_length, is_polling; } * ed;
          
          if (dispatch_state == VLIB_NODE_STATE_INTERRUPT
              && v >= nm->polling_threshold_vector_length)
            {
              vlib_node_t * n = vlib_get_node (vm, node->node_index);
              n->state = VLIB_NODE_STATE_POLLING;
              node->state = VLIB_NODE_STATE_POLLING;
              ASSERT (! (node->flags & VLIB_NODE_FLAG_SWITCH_FROM_INTERRUPT_TO_POLLING_MODE));
              node->flags &= ~VLIB_NODE_FLAG_SWITCH_FROM_POLLING_TO_INTERRUPT_MODE;
              node->flags |= VLIB_NODE_FLAG_SWITCH_FROM_INTERRUPT_TO_POLLING_MODE;
              nm->input_node_counts_by_state[VLIB_NODE_STATE_INTERRUPT] -= 1;
              nm->input_node_counts_by_state[VLIB_NODE_STATE_POLLING] += 1;

              ed = ELOG_DATA (&vm->elog_main, e);
              ed->node_name = n->name_elog_string;
              ed->vector_length = v;
              ed->is_polling = 1;
            }
          else if (dispatch_state == VLIB_NODE_STATE_POLLING
                   && v <= nm->interrupt_threshold_vector_length)
            {
              vlib_node_t * n = vlib_get_node (vm, node->node_index);
              if (node->flags & VLIB_NODE_FLAG_SWITCH_FROM_POLLING_TO_INTERRUPT_MODE)
                {
                  /* Switch to interrupt mode after dispatch in polling one more time.
                     This allows driver to re-enable interrupts. */
                  n->state = VLIB_NODE_STATE_INTERRUPT;
                  node->state = VLIB_NODE_STATE_INTERRUPT;
                  node->flags &= ~VLIB_NODE_FLAG_SWITCH_FROM_INTERRUPT_TO_POLLING_MODE;
                  nm->input_node_counts_by_state[VLIB_NODE_STATE_POLLING] -= 1;
                  nm->input_node_counts_by_state[VLIB_NODE_STATE_INTERRUPT] += 1;

                }
              else
                {
                  node->flags |= VLIB_NODE_FLAG_SWITCH_FROM_POLLING_TO_INTERRUPT_MODE;
                  ed = ELOG_DATA (&vm->elog_main, e);
                  ed->node_name = n->name_elog_string;
                  ed->vector_length = v;
                  ed->is_polling = 0;
                }
            }
        }
    }

  return t;
}

/* static */ u64
dispatch_pending_node (vlib_main_t * vm,
                       vlib_pending_frame_t * p,
                       u64 last_time_stamp)
{
  vlib_node_main_t * nm = &vm->node_main;
  vlib_frame_t * f;
  vlib_next_frame_t * nf, nf_dummy;
  vlib_node_runtime_t * n;
  u32 restore_frame_index;

  n = vec_elt_at_index (nm->nodes_by_type[VLIB_NODE_TYPE_INTERNAL],
                        p->node_runtime_index);

  f = vlib_get_frame (vm, p->frame_index);
  if (p->next_frame_index == VLIB_PENDING_FRAME_NO_NEXT_FRAME)
    {
      /* No next frame: so use dummy on stack. */
      nf = &nf_dummy;
      nf->flags = f->flags & VLIB_NODE_FLAG_TRACE;
      nf->frame_index = ~p->frame_index;
    }
  else
    nf = vec_elt_at_index (nm->next_frames, p->next_frame_index);

  ASSERT (f->flags & VLIB_FRAME_IS_ALLOCATED);

  /* Force allocation of new frame while current frame is being
     dispatched. */
  restore_frame_index = ~0;
  if (nf->frame_index == p->frame_index)
    {
      nf->frame_index = ~0;
      nf->flags &= ~VLIB_FRAME_IS_ALLOCATED;
      if (! (n->flags & VLIB_NODE_FLAG_FRAME_NO_FREE_AFTER_DISPATCH))
        restore_frame_index = p->frame_index;
    }

  /* Frame must be pending. */
  ASSERT (f->flags & VLIB_FRAME_PENDING);
  ASSERT (f->n_vectors > 0);

  /* Copy trace flag from next frame to node.
     Trace flag indicates that at least one vector in the dispatched
     frame is traced. */
  n->flags &= ~VLIB_NODE_FLAG_TRACE;
  n->flags |= (nf->flags & VLIB_FRAME_TRACE) ? VLIB_NODE_FLAG_TRACE : 0;
  nf->flags &= ~VLIB_FRAME_TRACE;

  last_time_stamp = dispatch_node (vm, n,
                                   VLIB_NODE_TYPE_INTERNAL,
                                   VLIB_NODE_STATE_POLLING,
                                   f, last_time_stamp);

  f->flags &= ~VLIB_FRAME_PENDING;

  /* Frame is ready to be used again, so restore it. */
  if (restore_frame_index != ~0)
    {
      /* p->next_frame_index can change during node dispatch if node
         function decides to change graph hook up. */
      nf = vec_elt_at_index (nm->next_frames, p->next_frame_index);
      nf->frame_index = restore_frame_index;
      nf->flags |= VLIB_FRAME_IS_ALLOCATED;
    }

  if (f->flags & VLIB_FRAME_FREE_AFTER_DISPATCH)
    {
      ASSERT (! (n->flags & VLIB_NODE_FLAG_FRAME_NO_FREE_AFTER_DISPATCH));
      vlib_frame_free (vm, n, f);
    }

  return last_time_stamp;
}

always_inline uword
vlib_process_stack_is_valid (vlib_process_t * p)
{ return p->stack[0] == VLIB_PROCESS_STACK_MAGIC; }

typedef struct {
  vlib_main_t * vm;
  vlib_process_t * process;
  vlib_frame_t * frame;
} vlib_process_bootstrap_args_t;

/* Called in process stack. */
static uword vlib_process_bootstrap (uword _a)
{
  vlib_process_bootstrap_args_t * a;
  vlib_main_t * vm;
  vlib_node_runtime_t * node;
  vlib_frame_t * f;
  vlib_process_t * p;
  uword n;

  a = uword_to_pointer (_a, vlib_process_bootstrap_args_t *);

  vm = a->vm;
  p = a->process;
  f = a->frame;
  node = &p->node_runtime;

  n = node->function (vm, node, f);

  ASSERT (vlib_process_stack_is_valid (p));

  clib_longjmp (&p->return_longjmp, n);

  return n;
}

/* Called in main stack. */
static_always_inline uword
vlib_process_startup (vlib_main_t * vm,
                      vlib_process_t * p,
                      vlib_frame_t * f)
{
  vlib_process_bootstrap_args_t a;
  uword r;

  a.vm = vm;
  a.process = p;
  a.frame = f;

  r = clib_setjmp (&p->return_longjmp, VLIB_PROCESS_RETURN_LONGJMP_RETURN);
  if (r == VLIB_PROCESS_RETURN_LONGJMP_RETURN)
    r = clib_calljmp (vlib_process_bootstrap, pointer_to_uword (&a),
                      (void *) p->stack + (1 << p->log2_n_stack_bytes));

  return r;
}

static_always_inline uword
vlib_process_resume (vlib_process_t * p)
{
  uword r;
  p->flags &= ~(VLIB_PROCESS_IS_SUSPENDED_WAITING_FOR_CLOCK
                | VLIB_PROCESS_IS_SUSPENDED_WAITING_FOR_EVENT
                | VLIB_PROCESS_RESUME_PENDING);
  r = clib_setjmp (&p->return_longjmp, VLIB_PROCESS_RETURN_LONGJMP_RETURN);
  if (r == VLIB_PROCESS_RETURN_LONGJMP_RETURN)
    clib_longjmp (&p->resume_longjmp, VLIB_PROCESS_RESUME_LONGJMP_RESUME);
  return r;
}

static u64
dispatch_process (vlib_main_t * vm,
                  vlib_process_t * p,
                  vlib_frame_t * f,
                  u64 last_time_stamp)
{
  vlib_node_main_t * nm = &vm->node_main;
  vlib_node_runtime_t * node_runtime = &p->node_runtime;
  vlib_node_t * node = vlib_get_node (vm, node_runtime->node_index);
  u64 t;
  uword n_vectors, is_suspend;

  if (node->state != VLIB_NODE_STATE_POLLING
      || (p->flags & (VLIB_PROCESS_IS_SUSPENDED_WAITING_FOR_CLOCK
                      | VLIB_PROCESS_IS_SUSPENDED_WAITING_FOR_EVENT)))
    return last_time_stamp;

  p->flags |= VLIB_PROCESS_IS_RUNNING;

  t = last_time_stamp;
  vlib_elog_main_loop_event (vm, node_runtime->node_index, t,
                             f ? f->n_vectors : 0, /* is_after */ 0);

  /* Save away current process for suspend. */
  nm->current_process_index = node->runtime_index;

  n_vectors = vlib_process_startup (vm, p, f);

  nm->current_process_index = ~0;

  ASSERT (n_vectors != VLIB_PROCESS_RETURN_LONGJMP_RETURN);
  is_suspend = n_vectors == VLIB_PROCESS_RETURN_LONGJMP_SUSPEND;
  if (is_suspend)
    {
      vlib_pending_frame_t * pf;

      n_vectors = 0;
      pool_get (nm->suspended_process_frames, pf);
      pf->node_runtime_index = node->runtime_index;
      pf->frame_index = f ? vlib_frame_index (vm, f) : ~0;
      pf->next_frame_index = ~0;

      p->n_suspends += 1;
      p->suspended_process_frame_index = pf - nm->suspended_process_frames;

      if (p->flags & VLIB_PROCESS_IS_SUSPENDED_WAITING_FOR_CLOCK)
        timing_wheel_insert (&nm->timing_wheel, p->resume_cpu_time,
                             vlib_timing_wheel_data_set_suspended_process (node->runtime_index));
    }
  else
    p->flags &= ~VLIB_PROCESS_IS_RUNNING;

  t = clib_cpu_time_now ();

  vlib_elog_main_loop_event (vm, node_runtime->node_index, t, is_suspend, /* is_after */ 1);

  vlib_process_update_stats (vm, p,
                             /* n_calls */ ! is_suspend,
                             /* n_vectors */ n_vectors,
                             /* n_clocks */ t - last_time_stamp);

  return t;
}

void vlib_start_process (vlib_main_t * vm, uword process_index)
{
  vlib_node_main_t * nm = &vm->node_main;
  vlib_process_t * p = vec_elt (nm->processes, process_index);
  dispatch_process (vm, p, /* frame */ 0, /* cpu_time_now */ 0);
}

static u64
dispatch_suspended_process (vlib_main_t * vm,
                            uword process_index,
                            u64 last_time_stamp)
{
  vlib_node_main_t * nm = &vm->node_main;
  vlib_node_runtime_t * node_runtime;
  vlib_node_t * node;
  vlib_frame_t * f;
  vlib_process_t * p;
  vlib_pending_frame_t * pf;
  u64 t, n_vectors, is_suspend;
  
  t = last_time_stamp;

  p = vec_elt (nm->processes, process_index);
  if (PREDICT_FALSE (! (p->flags & VLIB_PROCESS_IS_RUNNING)))
    return last_time_stamp;

  ASSERT (p->flags & (VLIB_PROCESS_IS_SUSPENDED_WAITING_FOR_CLOCK
                      | VLIB_PROCESS_IS_SUSPENDED_WAITING_FOR_EVENT));

  pf = pool_elt_at_index (nm->suspended_process_frames, p->suspended_process_frame_index);

  node_runtime = &p->node_runtime;
  node = vlib_get_node (vm, node_runtime->node_index);
  f = pf->frame_index != ~0 ? vlib_get_frame (vm, pf->frame_index) : 0;

  vlib_elog_main_loop_event (vm, node_runtime->node_index, t, f ? f->n_vectors : 0, /* is_after */ 0);

  /* Save away current process for suspend. */
  nm->current_process_index = node->runtime_index;

  n_vectors = vlib_process_resume (p);
  t = clib_cpu_time_now ();

  nm->current_process_index = ~0;

  is_suspend = n_vectors == VLIB_PROCESS_RETURN_LONGJMP_SUSPEND;
  if (is_suspend)
    {
      /* Suspend it again. */
      n_vectors = 0;
      p->n_suspends += 1;
      if (p->flags & VLIB_PROCESS_IS_SUSPENDED_WAITING_FOR_CLOCK)
        timing_wheel_insert (&nm->timing_wheel, p->resume_cpu_time,
                             vlib_timing_wheel_data_set_suspended_process (node->runtime_index));
    }
  else
    {
      p->flags &= ~VLIB_PROCESS_IS_RUNNING;
      p->suspended_process_frame_index = ~0;
      pool_put (nm->suspended_process_frames, pf);
    }

  t = clib_cpu_time_now ();
  vlib_elog_main_loop_event (vm, node_runtime->node_index, t, ! is_suspend, /* is_after */ 1);

  vlib_process_update_stats (vm, p,
                             /* n_calls */ ! is_suspend,
                             /* n_vectors */ n_vectors,
                             /* n_clocks */ t - last_time_stamp);

  return t;
}

static void vlib_main_loop (vlib_main_t * vm)
{
  vlib_node_main_t * nm = &vm->node_main;
  uword i;
  u64 cpu_time_now;

  /* Initialize pending node vector. */
  vec_resize (nm->pending_frames, 32);
  _vec_len (nm->pending_frames) = 0;

  /* Mark time of main loop start. */
  cpu_time_now = vm->clib_time.last_cpu_time;
  vm->cpu_time_main_loop_start = cpu_time_now;

  /* Arrange for first level of timing wheel to cover times we care
     most about. */
  nm->timing_wheel.min_sched_time = 10e-6;
  nm->timing_wheel.max_sched_time = 10e-3;
  timing_wheel_init (&nm->timing_wheel,
                     cpu_time_now,
                     vm->clib_time.clocks_per_second);

  /* Pre-allocate expired nodes. */
  vec_alloc (nm->data_from_advancing_timing_wheel, 32);
  vec_alloc (nm->pending_interrupt_node_runtime_indices, 32);

  if (! nm->polling_threshold_vector_length)
    nm->polling_threshold_vector_length = 10;
  if (! nm->interrupt_threshold_vector_length)
    nm->interrupt_threshold_vector_length = 5;

  nm->current_process_index = ~0;

  /* Start all processes. */
  {
    uword i;
    for (i = 0; i < vec_len (nm->processes); i++)
      cpu_time_now = dispatch_process (vm, nm->processes[i], /* frame */ 0, cpu_time_now);
  }

  while (1)
    {
      vlib_node_runtime_t * n;

      /* Process pre-input nodes. */
      vec_foreach (n, nm->nodes_by_type[VLIB_NODE_TYPE_PRE_INPUT])
        cpu_time_now = dispatch_node (vm, n,
                                      VLIB_NODE_TYPE_PRE_INPUT,
                                      VLIB_NODE_STATE_POLLING,
                                      /* frame */ 0,
                                      cpu_time_now);

      /* Next process input nodes. */
      vec_foreach (n, nm->nodes_by_type[VLIB_NODE_TYPE_INPUT])
        cpu_time_now = dispatch_node (vm, n,
                                      VLIB_NODE_TYPE_INPUT,
                                      VLIB_NODE_STATE_POLLING,
                                      /* frame */ 0,
                                      cpu_time_now);

      if (PREDICT_TRUE (vm->queue_signal_pending == 0))
          vm->queue_signal_callback (vm);

      /* Next handle interrupts. */
      {
        uword l = _vec_len (nm->pending_interrupt_node_runtime_indices);
        uword i;
        if (l > 0)
          {
            _vec_len (nm->pending_interrupt_node_runtime_indices) = 0;
            for (i = 0; i < l; i++)
              {
                n = vec_elt_at_index (nm->nodes_by_type[VLIB_NODE_TYPE_INPUT],
                                      nm->pending_interrupt_node_runtime_indices[i]);
                cpu_time_now = dispatch_node (vm, n,
                                              VLIB_NODE_TYPE_INPUT,
                                              VLIB_NODE_STATE_INTERRUPT,
                                              /* frame */ 0,
                                              cpu_time_now);
              }
          }
      }

      /* Check if process nodes have expired from timing wheel. */
      nm->data_from_advancing_timing_wheel
        = timing_wheel_advance (&nm->timing_wheel, cpu_time_now,
                                nm->data_from_advancing_timing_wheel,
                                &nm->cpu_time_next_process_ready);

      ASSERT (nm->data_from_advancing_timing_wheel != 0);
      if (PREDICT_FALSE (_vec_len (nm->data_from_advancing_timing_wheel) > 0))
        {
          uword i;

        processes_timing_wheel_data:
          for (i = 0; i < _vec_len (nm->data_from_advancing_timing_wheel); i++)
            {
              u32 d = nm->data_from_advancing_timing_wheel[i];
              u32 di = vlib_timing_wheel_data_get_index (d);

              if (vlib_timing_wheel_data_is_timed_event (d))
                {
                  vlib_signal_timed_event_data_t * te = pool_elt_at_index (nm->signal_timed_event_data_pool, di);
                  vlib_node_t * n = vlib_get_node (vm, te->process_node_index);
                  vlib_process_t * p = vec_elt (nm->processes, n->runtime_index);
                  void * data;
                  data = vlib_process_signal_event_helper (nm, n, p, te->event_type_index, te->n_data_elts, te->n_data_elt_bytes);
                  if (te->n_data_bytes < sizeof (te->inline_event_data))
                    clib_memcpy (data, te->inline_event_data, te->n_data_bytes);
                  else
                    {
                      clib_memcpy (data, te->event_data_as_vector, te->n_data_bytes);
                      vec_free (te->event_data_as_vector);
                    }
                  pool_put (nm->signal_timed_event_data_pool, te);
                }
              else
                {
                  cpu_time_now = clib_cpu_time_now();
                  cpu_time_now = dispatch_suspended_process (vm, di, cpu_time_now);
                }
            }

          /* Reset vector. */
          _vec_len (nm->data_from_advancing_timing_wheel) = 0;
        }

      /* Input nodes may have added work to the pending vector.
         Process pending vector until there is nothing left.
         All pending vectors will be processed from input -> output. */
      for (i = 0; i < _vec_len (nm->pending_frames); i++)
          cpu_time_now = dispatch_pending_node (vm, nm->pending_frames + i,
                                                cpu_time_now);
      /* Reset pending vector for next iteration. */
      _vec_len (nm->pending_frames) = 0;
      
      /* Pending internal nodes may resume processes. */
      if (_vec_len (nm->data_from_advancing_timing_wheel) > 0)
        goto processes_timing_wheel_data;

      vlib_increment_main_loop_counter (vm);

      /* Record time stamp in case there are no enabled nodes and above
         calls do not update time stamp. */
      cpu_time_now = clib_cpu_time_now ();
    }
}
               
vlib_main_t vlib_global_main;

static clib_error_t *
vlib_main_configure (vlib_main_t * vm, unformat_input_t * input)
{
  int turn_on_mem_trace = 0;

  while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
    {
      if (unformat (input, "memory-trace"))
        turn_on_mem_trace = 1;

      else if (unformat (input, "elog-events %d",
                         &vm->elog_main.event_ring_size))
        ;
      else
        return unformat_parse_error (input);
    }

  unformat_free (input);

  /* Enable memory trace as early as possible. */
  if (turn_on_mem_trace)
    clib_mem_trace (1);

  return 0;
}

VLIB_EARLY_CONFIG_FUNCTION (vlib_main_configure, "vlib");

static void dummy_queue_signal_callback (vlib_main_t * vm) { }

/* Main function. */
int vlib_main (vlib_main_t * vm, unformat_input_t * input)
{
  clib_error_t * error;

  vm->queue_signal_callback = dummy_queue_signal_callback;

  clib_time_init (&vm->clib_time);

  /* Turn on event log. */
  if (! vm->elog_main.event_ring_size)
    vm->elog_main.event_ring_size = 128 << 10;
  elog_init (&vm->elog_main, vm->elog_main.event_ring_size);
  elog_enable_disable (&vm->elog_main, 1);

  /* Default name. */
  if (! vm->name)
    vm->name = "VLIB";

  vec_validate (vm->buffer_main, 0);

  if ((error = vlib_thread_init (vm)))
    {
      clib_error_report (error);
      goto done;
    }

  /* Register static nodes so that init functions may use them. */
  vlib_register_all_static_nodes (vm);

  /* Set seed for random number generator.
     Allow user to specify seed to make random sequence deterministic. */
  if (! unformat (input, "seed %wd", &vm->random_seed))
    vm->random_seed = clib_cpu_time_now ();
  clib_random_buffer_init (&vm->random_buffer, vm->random_seed);

  /* See unix/main.c; most likely already set up */
  if (vm->init_functions_called == 0)
      vm->init_functions_called = hash_create (0, /* value bytes */ 0);
  if ((error = vlib_call_all_init_functions (vm)))
    goto done;

  /* Initialize node graph. */
  if ((error = vlib_node_main_init (vm)))
    {
      /* Arrange for graph hook up error to not be fatal when debugging. */
      if (CLIB_DEBUG > 0)
        clib_error_report (error);
      else
        goto done;
    }

  /* Create default buffer free list. */
  vlib_buffer_get_or_create_free_list (vm, VLIB_BUFFER_DEFAULT_FREE_LIST_BYTES,
                                       "default");

  switch (clib_setjmp (&vm->main_loop_exit, VLIB_MAIN_LOOP_EXIT_NONE))
    {
    case VLIB_MAIN_LOOP_EXIT_NONE:
      vm->main_loop_exit_set = 1;
      break;

    case VLIB_MAIN_LOOP_EXIT_CLI:
      goto done;

    default:
      error = vm->main_loop_error;
      goto done;
    }

  if ((error = vlib_call_all_config_functions (vm, input, 0 /* is_early */)))
    goto done;

  /* Call all main loop enter functions. */
  {
    clib_error_t * sub_error;
    sub_error = vlib_call_all_main_loop_enter_functions (vm);
    if (sub_error)
      clib_error_report (sub_error);
  }

  vlib_main_loop (vm);

 done:
  /* Call all exit functions. */
  {
    clib_error_t * sub_error;
    sub_error = vlib_call_all_main_loop_exit_functions (vm);
    if (sub_error)
      clib_error_report (sub_error);
  }

  if (error)
    clib_error_report (error);

  return 0;
}