vppinfra: refactor clib_timebase_t
[vpp.git] / src / vlib / threads.c
index c99458d..e9d9cb5 100644 (file)
 #include <signal.h>
 #include <math.h>
 #include <vppinfra/format.h>
+#include <vppinfra/time_range.h>
 #include <vppinfra/linux/sysfs.h>
 #include <vlib/vlib.h>
 
 #include <vlib/threads.h>
 #include <vlib/unix/cj.h>
 
+#include <vlib/stat_weak_inlines.h>
+
 DECLARE_CJ_GLOBAL_LOG;
 
-#define FRAME_QUEUE_NELTS 64
 
 u32
 vl (void *p)
@@ -43,28 +45,6 @@ vlib_thread_main_t vlib_thread_main;
  * imapacts observed timings.
  */
 
-u32
-elog_global_id_for_msg_name (const char *msg_name)
-{
-  uword *p, r;
-  static uword *h;
-  u8 *name_copy;
-
-  if (!h)
-    h = hash_create_string (0, sizeof (uword));
-
-  p = hash_get_mem (h, msg_name);
-  if (p)
-    return p[0];
-  r = elog_string (&vlib_global_main.elog_main, "%s", msg_name);
-
-  name_copy = format (0, "%s%c", msg_name, 0);
-
-  hash_set_mem (h, name_copy, r);
-
-  return r;
-}
-
 static inline void
 barrier_trace_sync (f64 t_entry, f64 t_open, f64 t_closed)
 {
@@ -85,8 +65,8 @@ barrier_trace_sync (f64 t_entry, f64 t_open, f64 t_closed)
 
   ed = ELOG_DATA (&vlib_global_main.elog_main, e);
   ed->count = (int) vlib_worker_threads[0].barrier_sync_count;
-  ed->caller = elog_global_id_for_msg_name
-    (vlib_worker_threads[0].barrier_caller);
+  ed->caller = elog_string (&vlib_global_main.elog_main,
+                           (char *) vlib_worker_threads[0].barrier_caller);
   ed->t_entry = (int) (1000000.0 * t_entry);
   ed->t_open = (int) (1000000.0 * t_open);
   ed->t_closed = (int) (1000000.0 * t_closed);
@@ -112,8 +92,8 @@ barrier_trace_sync_rec (f64 t_entry)
 
   ed = ELOG_DATA (&vlib_global_main.elog_main, e);
   ed->depth = (int) vlib_worker_threads[0].recursion_level - 1;
-  ed->caller = elog_global_id_for_msg_name
-    (vlib_worker_threads[0].barrier_caller);
+  ed->caller = elog_string (&vlib_global_main.elog_main,
+                           (char *) vlib_worker_threads[0].barrier_caller);
 }
 
 static inline void
@@ -169,13 +149,7 @@ barrier_trace_release (f64 t_entry, f64 t_closed_total, f64 t_update_main)
 uword
 os_get_nthreads (void)
 {
-  u32 len;
-
-  len = vec_len (vlib_thread_stacks);
-  if (len == 0)
-    return 1;
-  else
-    return len;
+  return vec_len (vlib_thread_stacks);
 }
 
 void
@@ -282,6 +256,21 @@ vlib_thread_init (vlib_main_t * vm)
     }
   avail_cpu = clib_bitmap_set (avail_cpu, tm->main_lcore, 0);
 
+  /*
+   * Determine if the number of workers is greater than 0.
+   * If so, mark CPU 0 unavailable so workers will be numbered after main.
+   */
+  u32 n_workers = 0;
+  uword *p = hash_get_mem (tm->thread_registrations_by_name, "workers");
+  if (p != 0)
+    {
+      vlib_thread_registration_t *tr = (vlib_thread_registration_t *) p[0];
+      int worker_thread_count = tr->count;
+      n_workers = worker_thread_count;
+    }
+  if (tm->skip_cores == 0 && n_workers)
+    avail_cpu = clib_bitmap_set (avail_cpu, 0, 0);
+
   /* assume that there is socket 0 only if there is no data from sysfs */
   if (!tm->cpu_socket_bitmap)
     tm->cpu_socket_bitmap = clib_bitmap_set (0, 0, 1);
@@ -299,11 +288,8 @@ vlib_thread_init (vlib_main_t * vm)
       pthread_setaffinity_np (pthread_self (), sizeof (cpu_set_t), &cpuset);
     }
 
-  /* as many threads as stacks... */
-  vec_validate_aligned (vlib_worker_threads, vec_len (vlib_thread_stacks) - 1,
-                       CLIB_CACHE_LINE_BYTES);
-
-  /* Preallocate thread 0 */
+  /* Set up thread 0 */
+  vec_validate_aligned (vlib_worker_threads, 0, CLIB_CACHE_LINE_BYTES);
   _vec_len (vlib_worker_threads) = 1;
   w = vlib_worker_threads;
   w->thread_mheap = clib_mem_get_heap ();
@@ -313,6 +299,8 @@ vlib_thread_init (vlib_main_t * vm)
   w->thread_id = pthread_self ();
   tm->n_vlib_mains = 1;
 
+  vlib_get_thread_core_numa (w, w->cpu_id);
+
   if (tm->sched_policy != ~0)
     {
       struct sched_param sched_param;
@@ -358,8 +346,7 @@ vlib_thread_init (vlib_main_t * vm)
 
             avail_cpu = clib_bitmap_set(avail_cpu, c, 0);
           }));
-/* *INDENT-ON* */
-
+          /* *INDENT-ON* */
        }
       else
        {
@@ -381,9 +368,14 @@ vlib_thread_init (vlib_main_t * vm)
 
   tm->n_vlib_mains = n_vlib_mains;
 
+  /*
+   * Allocate the remaining worker threads, and thread stack vector slots
+   * from now on, calls to os_get_nthreads() will return the correct
+   * answer.
+   */
   vec_validate_aligned (vlib_worker_threads, first_index - 1,
                        CLIB_CACHE_LINE_BYTES);
-
+  vec_validate (vlib_thread_stacks, vec_len (vlib_worker_threads) - 1);
   return 0;
 }
 
@@ -603,24 +595,38 @@ vlib_worker_thread_bootstrap_fn (void *arg)
   return rv;
 }
 
-static void
-vlib_get_thread_core_socket (vlib_worker_thread_t * w, unsigned cpu_id)
+void
+vlib_get_thread_core_numa (vlib_worker_thread_t * w, unsigned cpu_id)
 {
   const char *sys_cpu_path = "/sys/devices/system/cpu/cpu";
+  const char *sys_node_path = "/sys/devices/system/node/node";
+  clib_bitmap_t *nbmp = 0, *cbmp = 0;
+  u32 node;
   u8 *p = 0;
-  int core_id = -1, socket_id = -1;
+  int core_id = -1, numa_id = -1;
 
   p = format (p, "%s%u/topology/core_id%c", sys_cpu_path, cpu_id, 0);
   clib_sysfs_read ((char *) p, "%d", &core_id);
   vec_reset_length (p);
-  p =
-    format (p, "%s%u/topology/physical_package_id%c", sys_cpu_path, cpu_id,
-           0);
-  clib_sysfs_read ((char *) p, "%d", &socket_id);
+
+  /* *INDENT-OFF* */
+  clib_sysfs_read ("/sys/devices/system/node/online", "%U",
+        unformat_bitmap_list, &nbmp);
+  clib_bitmap_foreach (node, nbmp, ({
+    p = format (p, "%s%u/cpulist%c", sys_node_path, node, 0);
+    clib_sysfs_read ((char *) p, "%U", unformat_bitmap_list, &cbmp);
+    if (clib_bitmap_get (cbmp, cpu_id))
+      numa_id = node;
+    vec_reset_length (cbmp);
+    vec_reset_length (p);
+  }));
+  /* *INDENT-ON* */
+  vec_free (nbmp);
+  vec_free (cbmp);
   vec_free (p);
 
   w->core_id = core_id;
-  w->socket_id = socket_id;
+  w->numa_id = numa_id;
 }
 
 static clib_error_t *
@@ -628,9 +634,28 @@ vlib_launch_thread_int (void *fp, vlib_worker_thread_t * w, unsigned cpu_id)
 {
   vlib_thread_main_t *tm = &vlib_thread_main;
   void *(*fp_arg) (void *) = fp;
+  void *numa_heap;
 
   w->cpu_id = cpu_id;
-  vlib_get_thread_core_socket (w, cpu_id);
+  vlib_get_thread_core_numa (w, cpu_id);
+
+  /* Set up NUMA-bound heap if indicated */
+  if (clib_per_numa_mheaps[w->numa_id] == 0)
+    {
+      /* If the user requested a NUMA heap, create it... */
+      if (tm->numa_heap_size)
+       {
+         numa_heap = clib_mem_init_thread_safe_numa
+           (0 /* DIY */ , tm->numa_heap_size, w->numa_id);
+         clib_per_numa_mheaps[w->numa_id] = numa_heap;
+       }
+      else
+       {
+         /* Or, use the main heap */
+         clib_per_numa_mheaps[w->numa_id] = w->thread_mheap;
+       }
+    }
+
   if (tm->cb.vlib_launch_thread_cb && !w->registration->use_pthreads)
     return tm->cb.vlib_launch_thread_cb (fp, (void *) w, cpu_id);
   else
@@ -699,6 +724,9 @@ start_workers (vlib_main_t * vm)
       vlib_worker_threads->node_reforks_required =
        clib_mem_alloc_aligned (sizeof (u32), CLIB_CACHE_LINE_BYTES);
 
+      /* We'll need the rpc vector lock... */
+      clib_spinlock_init (&vm->pending_rpc_lock);
+
       /* Ask for an initial barrier sync */
       *vlib_worker_threads->workers_at_barrier = 0;
       *vlib_worker_threads->wait_at_barrier = 1;
@@ -716,8 +744,6 @@ start_workers (vlib_main_t * vm)
       for (i = 0; i < vec_len (tm->registrations); i++)
        {
          vlib_node_main_t *nm, *nm_clone;
-         vlib_buffer_free_list_t *fl_clone, *fl_orig;
-         vlib_buffer_free_list_t *orig_freelist_pool;
          int k;
 
          tr = tm->registrations[i];
@@ -732,15 +758,8 @@ start_workers (vlib_main_t * vm)
              vec_add2 (vlib_worker_threads, w, 1);
              /* Currently unused, may not really work */
              if (tr->mheap_size)
-               {
-#if USE_DLMALLOC == 0
-                 w->thread_mheap =
-                   mheap_alloc (0 /* use VM */ , tr->mheap_size);
-#else
-                 w->thread_mheap = create_mspace (tr->mheap_size,
-                                                  0 /* unlocked */ );
-#endif
-               }
+               w->thread_mheap = create_mspace (tr->mheap_size,
+                                                0 /* unlocked */ );
              else
                w->thread_mheap = main_heap;
 
@@ -798,7 +817,7 @@ start_workers (vlib_main_t * vm)
 
              /* fork the frame dispatch queue */
              nm_clone->pending_frames = 0;
-             vec_validate (nm_clone->pending_frames, 10);      /* $$$$$?????? */
+             vec_validate (nm_clone->pending_frames, 10);
              _vec_len (nm_clone->pending_frames) = 0;
 
              /* fork nodes */
@@ -847,42 +866,47 @@ start_workers (vlib_main_t * vm)
                                         n->runtime_data_bytes));
              }
 
+             nm_clone->nodes_by_type[VLIB_NODE_TYPE_PRE_INPUT] =
+               vec_dup_aligned (nm->nodes_by_type[VLIB_NODE_TYPE_PRE_INPUT],
+                                CLIB_CACHE_LINE_BYTES);
+             vec_foreach (rt,
+                          nm_clone->nodes_by_type[VLIB_NODE_TYPE_PRE_INPUT])
+             {
+               vlib_node_t *n = vlib_get_node (vm, rt->node_index);
+               rt->thread_index = vm_clone->thread_index;
+               /* copy initial runtime_data from node */
+               if (n->runtime_data && n->runtime_data_bytes > 0)
+                 clib_memcpy (rt->runtime_data, n->runtime_data,
+                              clib_min (VLIB_NODE_RUNTIME_DATA_SIZE,
+                                        n->runtime_data_bytes));
+             }
+
              nm_clone->processes = vec_dup_aligned (nm->processes,
                                                     CLIB_CACHE_LINE_BYTES);
 
-             /* zap the (per worker) frame freelists, etc */
-             nm_clone->frame_sizes = 0;
+             /* Create per-thread frame freelist */
+             nm_clone->frame_sizes = vec_new (vlib_frame_size_t, 1);
+#ifdef VLIB_SUPPORTS_ARBITRARY_SCALAR_SIZES
              nm_clone->frame_size_hash = hash_create (0, sizeof (uword));
+#endif
+             nm_clone->node_by_error = nm->node_by_error;
 
              /* Packet trace buffers are guaranteed to be empty, nothing to do here */
 
              clib_mem_set_heap (oldheap);
              vec_add1_aligned (vlib_mains, vm_clone, CLIB_CACHE_LINE_BYTES);
 
+             /* Switch to the stats segment ... */
+             void *oldheap = vlib_stats_push_heap (0);
              vm_clone->error_main.counters = vec_dup_aligned
                (vlib_mains[0]->error_main.counters, CLIB_CACHE_LINE_BYTES);
+             vlib_stats_pop_heap2 (vm_clone->error_main.counters,
+                                   worker_thread_index, oldheap, 1);
+
              vm_clone->error_main.counters_last_clear = vec_dup_aligned
                (vlib_mains[0]->error_main.counters_last_clear,
                 CLIB_CACHE_LINE_BYTES);
 
-             /* Fork the vlib_buffer_main_t free lists, etc. */
-             orig_freelist_pool = vm_clone->buffer_free_list_pool;
-             vm_clone->buffer_free_list_pool = 0;
-
-            /* *INDENT-OFF* */
-            pool_foreach (fl_orig, orig_freelist_pool,
-                          ({
-                            pool_get_aligned (vm_clone->buffer_free_list_pool,
-                                              fl_clone, CLIB_CACHE_LINE_BYTES);
-                            ASSERT (fl_orig - orig_freelist_pool
-                                    == fl_clone - vm_clone->buffer_free_list_pool);
-
-                            fl_clone[0] = fl_orig[0];
-                            fl_clone->buffers = 0;
-                            fl_clone->n_alloc = 0;
-                          }));
-/* *INDENT-ON* */
-
              worker_thread_index++;
            }
        }
@@ -899,13 +923,8 @@ start_workers (vlib_main_t * vm)
              vec_add2 (vlib_worker_threads, w, 1);
              if (tr->mheap_size)
                {
-#if USE_DLMALLOC == 0
-                 w->thread_mheap =
-                   mheap_alloc (0 /* use VM */ , tr->mheap_size);
-#else
                  w->thread_mheap =
                    create_mspace (tr->mheap_size, 0 /* locked */ );
-#endif
                }
              else
                w->thread_mheap = main_heap;
@@ -1038,12 +1057,18 @@ vlib_worker_thread_node_refork (void)
   u64 *old_counters = vm_clone->error_main.counters;
   u64 *old_counters_all_clear = vm_clone->error_main.counters_last_clear;
 
-  clib_memcpy (&vm_clone->error_main, &vm->error_main,
-              sizeof (vm->error_main));
+  clib_memcpy_fast (&vm_clone->error_main, &vm->error_main,
+                   sizeof (vm->error_main));
   j = vec_len (vm->error_main.counters) - 1;
+
+  /* Switch to the stats segment ... */
+  void *oldheap = vlib_stats_push_heap (0);
   vec_validate_aligned (old_counters, j, CLIB_CACHE_LINE_BYTES);
-  vec_validate_aligned (old_counters_all_clear, j, CLIB_CACHE_LINE_BYTES);
   vm_clone->error_main.counters = old_counters;
+  vlib_stats_pop_heap2 (vm_clone->error_main.counters, vm_clone->thread_index,
+                       oldheap, 0);
+
+  vec_validate_aligned (old_counters_all_clear, j, CLIB_CACHE_LINE_BYTES);
   vm_clone->error_main.counters_last_clear = old_counters_all_clear;
 
   nm_clone = &vm_clone->node_main;
@@ -1074,13 +1099,9 @@ vlib_worker_thread_node_refork (void)
     clib_mem_alloc_no_fail (vec_len (nm->nodes) * sizeof (*new_n_clone));
   for (j = 0; j < vec_len (nm->nodes); j++)
     {
-      vlib_node_t *old_n_clone;
-      vlib_node_t *new_n;
-
-      new_n = nm->nodes[j];
-      old_n_clone = old_nodes_clone[j];
+      vlib_node_t *new_n = nm->nodes[j];
 
-      clib_memcpy (new_n_clone, new_n, sizeof (*new_n));
+      clib_memcpy_fast (new_n_clone, new_n, sizeof (*new_n));
       /* none of the copied nodes have enqueue rights given out */
       new_n_clone->owner_node_index = VLIB_INVALID_NODE_INDEX;
 
@@ -1094,13 +1115,14 @@ vlib_worker_thread_node_refork (void)
        }
       else
        {
+         vlib_node_t *old_n_clone = old_nodes_clone[j];
          /* Copy stats if the old data is valid */
-         clib_memcpy (&new_n_clone->stats_total,
-                      &old_n_clone->stats_total,
-                      sizeof (new_n_clone->stats_total));
-         clib_memcpy (&new_n_clone->stats_last_clear,
-                      &old_n_clone->stats_last_clear,
-                      sizeof (new_n_clone->stats_last_clear));
+         clib_memcpy_fast (&new_n_clone->stats_total,
+                           &old_n_clone->stats_total,
+                           sizeof (new_n_clone->stats_total));
+         clib_memcpy_fast (&new_n_clone->stats_last_clear,
+                           &old_n_clone->stats_last_clear,
+                           sizeof (new_n_clone->stats_last_clear));
 
          /* keep previous node state */
          new_n_clone->state = old_n_clone->state;
@@ -1126,17 +1148,17 @@ vlib_worker_thread_node_refork (void)
     rt->thread_index = vm_clone->thread_index;
     /* copy runtime_data, will be overwritten later for existing rt */
     if (n->runtime_data && n->runtime_data_bytes > 0)
-      clib_memcpy (rt->runtime_data, n->runtime_data,
-                  clib_min (VLIB_NODE_RUNTIME_DATA_SIZE,
-                            n->runtime_data_bytes));
+      clib_memcpy_fast (rt->runtime_data, n->runtime_data,
+                       clib_min (VLIB_NODE_RUNTIME_DATA_SIZE,
+                                 n->runtime_data_bytes));
   }
 
   for (j = 0; j < vec_len (old_rt); j++)
     {
       rt = vlib_node_get_runtime (vm_clone, old_rt[j].node_index);
       rt->state = old_rt[j].state;
-      clib_memcpy (rt->runtime_data, old_rt[j].runtime_data,
-                  VLIB_NODE_RUNTIME_DATA_SIZE);
+      clib_memcpy_fast (rt->runtime_data, old_rt[j].runtime_data,
+                       VLIB_NODE_RUNTIME_DATA_SIZE);
     }
 
   vec_free (old_rt);
@@ -1153,23 +1175,51 @@ vlib_worker_thread_node_refork (void)
     rt->thread_index = vm_clone->thread_index;
     /* copy runtime_data, will be overwritten later for existing rt */
     if (n->runtime_data && n->runtime_data_bytes > 0)
-      clib_memcpy (rt->runtime_data, n->runtime_data,
-                  clib_min (VLIB_NODE_RUNTIME_DATA_SIZE,
-                            n->runtime_data_bytes));
+      clib_memcpy_fast (rt->runtime_data, n->runtime_data,
+                       clib_min (VLIB_NODE_RUNTIME_DATA_SIZE,
+                                 n->runtime_data_bytes));
   }
 
   for (j = 0; j < vec_len (old_rt); j++)
     {
       rt = vlib_node_get_runtime (vm_clone, old_rt[j].node_index);
       rt->state = old_rt[j].state;
-      clib_memcpy (rt->runtime_data, old_rt[j].runtime_data,
-                  VLIB_NODE_RUNTIME_DATA_SIZE);
+      clib_memcpy_fast (rt->runtime_data, old_rt[j].runtime_data,
+                       VLIB_NODE_RUNTIME_DATA_SIZE);
+    }
+
+  vec_free (old_rt);
+
+  /* re-clone pre-input nodes */
+  old_rt = nm_clone->nodes_by_type[VLIB_NODE_TYPE_PRE_INPUT];
+  nm_clone->nodes_by_type[VLIB_NODE_TYPE_PRE_INPUT] =
+    vec_dup_aligned (nm->nodes_by_type[VLIB_NODE_TYPE_PRE_INPUT],
+                    CLIB_CACHE_LINE_BYTES);
+
+  vec_foreach (rt, nm_clone->nodes_by_type[VLIB_NODE_TYPE_PRE_INPUT])
+  {
+    vlib_node_t *n = vlib_get_node (vm, rt->node_index);
+    rt->thread_index = vm_clone->thread_index;
+    /* copy runtime_data, will be overwritten later for existing rt */
+    if (n->runtime_data && n->runtime_data_bytes > 0)
+      clib_memcpy_fast (rt->runtime_data, n->runtime_data,
+                       clib_min (VLIB_NODE_RUNTIME_DATA_SIZE,
+                                 n->runtime_data_bytes));
+  }
+
+  for (j = 0; j < vec_len (old_rt); j++)
+    {
+      rt = vlib_node_get_runtime (vm_clone, old_rt[j].node_index);
+      rt->state = old_rt[j].state;
+      clib_memcpy_fast (rt->runtime_data, old_rt[j].runtime_data,
+                       VLIB_NODE_RUNTIME_DATA_SIZE);
     }
 
   vec_free (old_rt);
 
   nm_clone->processes = vec_dup_aligned (nm->processes,
                                         CLIB_CACHE_LINE_BYTES);
+  nm_clone->node_by_error = nm->node_by_error;
 }
 
 void
@@ -1231,6 +1281,9 @@ cpu_config (vlib_main_t * vm, unformat_input_t * input)
        ;
       else if (unformat (input, "skip-cores %u", &tm->skip_cores))
        ;
+      else if (unformat (input, "numa-heap-size %U",
+                        unformat_memory_size, &tm->numa_heap_size))
+       ;
       else if (unformat (input, "coremask-%s %U", &name,
                         unformat_bitmap_mask, &bitmap) ||
               unformat (input, "corelist-%s %U", &name,
@@ -1355,20 +1408,48 @@ vlib_worker_thread_fork_fixup (vlib_fork_fixup_t which)
 #endif
 
 void
-vlib_worker_thread_barrier_sync_int (vlib_main_t * vm)
+vlib_worker_thread_initial_barrier_sync_and_release (vlib_main_t * vm)
+{
+  f64 deadline;
+  f64 now = vlib_time_now (vm);
+  u32 count = vec_len (vlib_mains) - 1;
+
+  /* No worker threads? */
+  if (count == 0)
+    return;
+
+  deadline = now + BARRIER_SYNC_TIMEOUT;
+  *vlib_worker_threads->wait_at_barrier = 1;
+  while (*vlib_worker_threads->workers_at_barrier != count)
+    {
+      if ((now = vlib_time_now (vm)) > deadline)
+       {
+         fformat (stderr, "%s: worker thread deadlock\n", __FUNCTION__);
+         os_panic ();
+       }
+      CLIB_PAUSE ();
+    }
+  *vlib_worker_threads->wait_at_barrier = 0;
+}
+
+void
+vlib_worker_thread_barrier_sync_int (vlib_main_t * vm, const char *func_name)
 {
   f64 deadline;
   f64 now;
   f64 t_entry;
   f64 t_open;
   f64 t_closed;
+  f64 max_vector_rate;
   u32 count;
+  int i;
 
   if (vec_len (vlib_mains) < 2)
     return;
 
   ASSERT (vlib_get_thread_index () == 0);
 
+  vlib_worker_threads[0].barrier_caller = func_name;
   count = vec_len (vlib_mains) - 1;
 
   /* Record entry relative to last close */
@@ -1382,23 +1463,41 @@ vlib_worker_thread_barrier_sync_int (vlib_main_t * vm)
       return;
     }
 
+  /*
+   * Need data to decide if we're working hard enough to honor
+   * the barrier hold-down timer.
+   */
+  max_vector_rate = 0.0;
+  for (i = 1; i < vec_len (vlib_mains); i++)
+    max_vector_rate =
+      clib_max (max_vector_rate,
+               (f64) vlib_last_vectors_per_main_loop (vlib_mains[i]));
+
   vlib_worker_threads[0].barrier_sync_count++;
 
   /* Enforce minimum barrier open time to minimize packet loss */
   ASSERT (vm->barrier_no_close_before <= (now + BARRIER_MINIMUM_OPEN_LIMIT));
 
-  while (1)
+  /*
+   * If any worker thread seems busy, which we define
+   * as a vector rate above 10, we enforce the barrier hold-down timer
+   */
+  if (max_vector_rate > 10.0)
     {
-      now = vlib_time_now (vm);
-      /* Barrier hold-down timer expired? */
-      if (now >= vm->barrier_no_close_before)
-       break;
-      if ((vm->barrier_no_close_before - now)
-         > (2.0 * BARRIER_MINIMUM_OPEN_LIMIT))
+      while (1)
        {
-         clib_warning ("clock change: would have waited for %.4f seconds",
-                       (vm->barrier_no_close_before - now));
-         break;
+         now = vlib_time_now (vm);
+         /* Barrier hold-down timer expired? */
+         if (now >= vm->barrier_no_close_before)
+           break;
+         if ((vm->barrier_no_close_before - now)
+             > (2.0 * BARRIER_MINIMUM_OPEN_LIMIT))
+           {
+             clib_warning
+               ("clock change: would have waited for %.4f seconds",
+                (vm->barrier_no_close_before - now));
+             break;
+           }
        }
     }
   /* Record time of closure */
@@ -1423,18 +1522,6 @@ vlib_worker_thread_barrier_sync_int (vlib_main_t * vm)
 
 }
 
-void vlib_stat_segment_lock (void) __attribute__ ((weak));
-void
-vlib_stat_segment_lock (void)
-{
-}
-
-void vlib_stat_segment_unlock (void) __attribute__ ((weak));
-void
-vlib_stat_segment_unlock (void)
-{
-}
-
 void
 vlib_worker_thread_barrier_release (vlib_main_t * vm)
 {
@@ -1485,6 +1572,14 @@ vlib_worker_thread_barrier_release (vlib_main_t * vm)
 
   deadline = now + BARRIER_SYNC_TIMEOUT;
 
+  /*
+   * Note when we let go of the barrier.
+   * Workers can use this to derive a reasonably accurate
+   * time offset. See vlib_time_now(...)
+   */
+  vm->time_last_barrier_release = vlib_time_now (vm);
+  CLIB_MEMORY_STORE_BARRIER ();
+
   *vlib_worker_threads->wait_at_barrier = 0;
 
   while (*vlib_worker_threads->workers_at_barrier > 0)
@@ -1597,6 +1692,7 @@ vlib_frame_queue_dequeue (vlib_main_t * vm, vlib_frame_queue_main_t * fqm)
 
   while (1)
     {
+      vlib_buffer_t *b;
       if (fq->head == fq->tail)
        {
          fq->head_hint = fq->head;
@@ -1619,6 +1715,11 @@ vlib_frame_queue_dequeue (vlib_main_t * vm, vlib_frame_queue_main_t * fqm)
 
       f = vlib_get_frame_to_node (vm, fqm->node_index);
 
+      /* If the first vector is traced, set the frame trace flag */
+      b = vlib_get_buffer (vm, from[0]);
+      if (b->flags & VLIB_BUFFER_IS_TRACED)
+       f->frame_flags |= VLIB_NODE_FLAG_TRACE;
+
       to = vlib_frame_vector_args (f);
 
       n_left_to_node = elt->n_vectors;
@@ -1680,15 +1781,15 @@ vlib_worker_thread_fn (void *arg)
   clib_time_init (&vm->clib_time);
   clib_mem_set_heap (w->thread_mheap);
 
+  e = vlib_call_init_exit_functions_no_sort
+    (vm, &vm->worker_init_function_registrations, 1 /* call_once */ );
+  if (e)
+    clib_error_report (e);
+
   /* Wait until the dpdk init sequence is complete */
   while (tm->extern_thread_mgmt && tm->worker_thread_release == 0)
     vlib_worker_thread_barrier_check ();
 
-  e = vlib_call_init_exit_functions
-    (vm, vm->worker_init_function_registrations, 1 /* call_once */ );
-  if (e)
-    clib_error_report (e);
-
   vlib_worker_loop (vm);
 }
 
@@ -1709,7 +1810,7 @@ vlib_frame_queue_main_init (u32 node_index, u32 frame_queue_nelts)
   int i;
 
   if (frame_queue_nelts == 0)
-    frame_queue_nelts = FRAME_QUEUE_NELTS;
+    frame_queue_nelts = FRAME_QUEUE_MAX_NELTS;
 
   ASSERT (frame_queue_nelts >= 8);
 
@@ -1783,6 +1884,55 @@ threads_init (vlib_main_t * vm)
 
 VLIB_INIT_FUNCTION (threads_init);
 
+
+static clib_error_t *
+show_clock_command_fn (vlib_main_t * vm,
+                      unformat_input_t * input, vlib_cli_command_t * cmd)
+{
+  int i;
+  int verbose = 0;
+  clib_timebase_t _tb, *tb = &_tb;
+
+  (void) unformat (input, "verbose %=", &verbose, 1);
+
+  clib_timebase_init (tb, 0 /* GMT */ , CLIB_TIMEBASE_DAYLIGHT_NONE,
+                     &vm->clib_time);
+
+  vlib_cli_output (vm, "%U, %U GMT", format_clib_time, &vm->clib_time,
+                  verbose, format_clib_timebase_time,
+                  clib_timebase_now (tb));
+
+  if (vec_len (vlib_mains) == 1)
+    return 0;
+
+  vlib_cli_output (vm, "Time last barrier release %.9f",
+                  vm->time_last_barrier_release);
+
+  for (i = 1; i < vec_len (vlib_mains); i++)
+    {
+      if (vlib_mains[i] == 0)
+       continue;
+
+      vlib_cli_output (vm, "%d: %U", i, format_clib_time,
+                      &vlib_mains[i]->clib_time, verbose);
+
+      vlib_cli_output (vm, "Thread %d offset %.9f error %.9f", i,
+                      vlib_mains[i]->time_offset,
+                      vm->time_last_barrier_release -
+                      vlib_mains[i]->time_last_barrier_release);
+    }
+  return 0;
+}
+
+/* *INDENT-OFF* */
+VLIB_CLI_COMMAND (f_command, static) =
+{
+  .path = "show clock",
+  .short_help = "show clock",
+  .function = show_clock_command_fn,
+};
+/* *INDENT-ON* */
+
 /*
  * fd.io coding-style-patch-verification: ON
  *