src/plugins/perfmon/perfmon_periodic.c - fdio/vpp - Gitiles

 /*
  * perfmon_periodic.c - skeleton plug-in periodic function
  *
  * Copyright (c) <current-year> <your-organization>
  * 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.
  */

 #include <vlib/vlib.h>
 #include <vppinfra/error.h>
 #include <perfmon/perfmon.h>
 #include <asm/unistd.h>
 #include <sys/ioctl.h>

 static long
 perf_event_open (struct perf_event_attr *hw_event, pid_t pid, int cpu,
 		 int group_fd, unsigned long flags)
 {
   int ret;

   ret = syscall (__NR_perf_event_open, hw_event, pid, cpu, group_fd, flags);
   return ret;
 }

 static u64
 read_current_perf_counter (vlib_main_t * vm)
 {
   if (vm->perf_counter_id)
     return clib_rdpmc (vm->perf_counter_id);
   else
     {
       u64 sw_value;
       if (read (vm->perf_counter_fd, &sw_value, sizeof (sw_value)) !=
 	  sizeof (sw_value))
 	{
 	  clib_unix_warning ("counter read failed, disable collection...");
 	  vm->vlib_node_runtime_perf_counter_cb = 0;
 	  return 0ULL;
 	}
       return sw_value;
     }
 }

 static void
 clear_counters (perfmon_main_t * pm)
 {
   int i, j;
   vlib_main_t *vm = pm->vlib_main;
   vlib_main_t *stat_vm;
   vlib_node_main_t *nm;
   vlib_node_t *n;

   vlib_worker_thread_barrier_sync (vm);

   for (j = 0; j < vec_len (vlib_mains); j++)
     {
       stat_vm = vlib_mains[j];
       if (stat_vm == 0)
 	continue;

       nm = &stat_vm->node_main;

       /* Clear the node runtime perfmon counters */
       for (i = 0; i < vec_len (nm->nodes); i++)
 	{
 	  n = nm->nodes[i];
 	  vlib_node_sync_stats (stat_vm, n);
 	}

       /* And clear the node perfmon counters */
       for (i = 0; i < vec_len (nm->nodes); i++)
 	{
 	  n = nm->nodes[i];
 	  n->stats_total.perf_counter_ticks = 0;
 	  n->stats_total.perf_counter_vectors = 0;
 	  n->stats_last_clear.perf_counter_ticks = 0;
 	  n->stats_last_clear.perf_counter_vectors = 0;
 	}
     }
   vlib_worker_thread_barrier_release (vm);
 }

 static void
 enable_current_event (perfmon_main_t * pm)
 {
   struct perf_event_attr pe;
   int fd;
   struct perf_event_mmap_page *p = 0;
   perfmon_event_config_t *c;
   vlib_main_t *vm = vlib_get_main ();
   u32 my_thread_index = vm->thread_index;

   c = vec_elt_at_index (pm->events_to_collect, pm->current_event);

   memset (&pe, 0, sizeof (struct perf_event_attr));
   pe.type = c->pe_type;
   pe.size = sizeof (struct perf_event_attr);
   pe.config = c->pe_config;
   pe.disabled = 1;
   pe.pinned = 1;
   /*
    * Note: excluding the kernel makes the
    * (software) context-switch counter read 0...
    */
   if (pe.type != PERF_TYPE_SOFTWARE)
     {
       /* Exclude kernel and hypervisor */
       pe.exclude_kernel = 1;
       pe.exclude_hv = 1;
     }

   fd = perf_event_open (&pe, 0, -1, -1, 0);
   if (fd == -1)
     {
       clib_unix_warning ("event open: type %d config %d", c->pe_type,
 			 c->pe_config);
       return;
     }

   if (pe.type != PERF_TYPE_SOFTWARE)
     {
       p = mmap (0, pm->page_size, PROT_READ, MAP_SHARED, fd, 0);
       if (p == MAP_FAILED)
 	{
 	  clib_unix_warning ("mmap");
 	  close (fd);
 	  return;
 	}
     }

   if (ioctl (fd, PERF_EVENT_IOC_RESET, 0) < 0)
     clib_unix_warning ("reset ioctl");

   if (ioctl (fd, PERF_EVENT_IOC_ENABLE, 0) < 0)
     clib_unix_warning ("enable ioctl");

   /*
    * Software event counters - and others not capable of being
    * read via the "rdpmc" instruction - will be read
    * by system calls.
    */
   if (pe.type == PERF_TYPE_SOFTWARE || p->cap_user_rdpmc == 0)
     pm->rdpmc_indices[my_thread_index] = 0;
   else				/* use rdpmc instrs */
     pm->rdpmc_indices[my_thread_index] = p->index - 1;
   pm->perf_event_pages[my_thread_index] = (void *) p;

   pm->pm_fds[my_thread_index] = fd;

   /* Enable the main loop counter snapshot mechanism */
   vm->perf_counter_id = pm->rdpmc_indices[my_thread_index];
   vm->perf_counter_fd = fd;
   vm->vlib_node_runtime_perf_counter_cb = read_current_perf_counter;
 }

 static void
 disable_event (perfmon_main_t * pm)
 {
   vlib_main_t *vm = vlib_get_main ();
   u32 my_thread_index = vm->thread_index;

   if (pm->pm_fds[my_thread_index] == 0)
     return;

   /* Stop main loop collection */
   vm->vlib_node_runtime_perf_counter_cb = 0;

   if (ioctl (pm->pm_fds[my_thread_index], PERF_EVENT_IOC_DISABLE, 0) < 0)
     clib_unix_warning ("disable ioctl");

   if (pm->perf_event_pages[my_thread_index])
     if (munmap (pm->perf_event_pages[my_thread_index], pm->page_size) < 0)
       clib_unix_warning ("munmap");

   (void) close (pm->pm_fds[my_thread_index]);
   pm->pm_fds[my_thread_index] = 0;
 }

 static void
 worker_thread_start_event (vlib_main_t * vm)
 {
   perfmon_main_t *pm = &perfmon_main;

   enable_current_event (pm);
   vm->worker_thread_main_loop_callback = 0;
 }

 static void
 worker_thread_stop_event (vlib_main_t * vm)
 {
   perfmon_main_t *pm = &perfmon_main;
   disable_event (pm);
   vm->worker_thread_main_loop_callback = 0;
 }

 static void
 start_event (perfmon_main_t * pm, f64 now, uword event_data)
 {
   int i;
   pm->current_event = 0;
   if (vec_len (pm->events_to_collect) == 0)
     {
       pm->state = PERFMON_STATE_OFF;
       return;
     }
   pm->state = PERFMON_STATE_RUNNING;
   clear_counters (pm);

   /* Start collection on this thread */
   enable_current_event (pm);

   /* And also on worker threads */
   for (i = 1; i < vec_len (vlib_mains); i++)
     {
       if (vlib_mains[i] == 0)
 	continue;
       vlib_mains[i]->worker_thread_main_loop_callback = (void *)
 	worker_thread_start_event;
     }
 }

 void
 scrape_and_clear_counters (perfmon_main_t * pm)
 {
   int i, j;
   vlib_main_t *vm = pm->vlib_main;
   vlib_main_t *stat_vm;
   vlib_node_main_t *nm;
   vlib_node_t ***node_dups = 0;
   vlib_node_t **nodes;
   vlib_node_t *n;
   perfmon_capture_t *c;
   perfmon_event_config_t *current_event;
   uword *p;
   u8 *counter_name;
   u64 counter_value;
   u64 vectors_this_counter;

   /* snapshoot the nodes, including pm counters */
   vlib_worker_thread_barrier_sync (vm);

   for (j = 0; j < vec_len (vlib_mains); j++)
     {
       stat_vm = vlib_mains[j];
       if (stat_vm == 0)
 	continue;

       nm = &stat_vm->node_main;

       for (i = 0; i < vec_len (nm->nodes); i++)
 	{
 	  n = nm->nodes[i];
 	  vlib_node_sync_stats (stat_vm, n);
 	}

       nodes = 0;
       vec_validate (nodes, vec_len (nm->nodes) - 1);
       vec_add1 (node_dups, nodes);

       /* Snapshoot and clear the per-node perfmon counters */
       for (i = 0; i < vec_len (nm->nodes); i++)
 	{
 	  n = nm->nodes[i];
 	  nodes[i] = clib_mem_alloc (sizeof (*n));
 	  clib_memcpy_fast (nodes[i], n, sizeof (*n));
 	  n->stats_total.perf_counter_ticks = 0;
 	  n->stats_total.perf_counter_vectors = 0;
 	  n->stats_last_clear.perf_counter_ticks = 0;
 	  n->stats_last_clear.perf_counter_vectors = 0;
 	}
     }

   vlib_worker_thread_barrier_release (vm);

   current_event = pm->events_to_collect + pm->current_event;

   for (j = 0; j < vec_len (vlib_mains); j++)
     {
       stat_vm = vlib_mains[j];
       if (stat_vm == 0)
 	continue;

       nodes = node_dups[j];

       for (i = 0; i < vec_len (nodes); i++)
 	{
 	  u8 *capture_name;

 	  n = nodes[i];
 	  if (n->stats_total.perf_counter_ticks == 0)
 	    {
 	      clib_mem_free (n);
 	      continue;
 	    }

 	  capture_name = format (0, "t%d-%v%c", j, n->name, 0);

 	  p = hash_get_mem (pm->capture_by_thread_and_node_name,
 			    capture_name);

 	  if (p == 0)
 	    {
 	      pool_get (pm->capture_pool, c);
 	      memset (c, 0, sizeof (*c));
 	      c->thread_and_node_name = capture_name;
 	      hash_set_mem (pm->capture_by_thread_and_node_name,
 			    capture_name, c - pm->capture_pool);
 	    }
 	  else
 	    c = pool_elt_at_index (pm->capture_pool, p[0]);

 	  /* Snapshoot counters, etc. into the capture */
 	  counter_name = (u8 *) current_event->name;
 	  counter_value = n->stats_total.perf_counter_ticks -
 	    n->stats_last_clear.perf_counter_ticks;
 	  vectors_this_counter = n->stats_total.perf_counter_vectors -
 	    n->stats_last_clear.perf_counter_vectors;

 	  vec_add1 (c->counter_names, counter_name);
 	  vec_add1 (c->counter_values, counter_value);
 	  vec_add1 (c->vectors_this_counter, vectors_this_counter);
 	  clib_mem_free (n);
 	}
       vec_free (nodes);
     }
   vec_free (node_dups);
 }

 static void
 handle_timeout (perfmon_main_t * pm, f64 now)
 {
   int i;
   disable_event (pm);

   /* And also on worker threads */
   for (i = 1; i < vec_len (vlib_mains); i++)
     {
       if (vlib_mains[i] == 0)
 	continue;
       vlib_mains[i]->worker_thread_main_loop_callback = (void *)
 	worker_thread_stop_event;
     }

   /* Short delay to make sure workers have stopped collection */
   if (i > 1)
     vlib_process_suspend (pm->vlib_main, 1e-3);
   scrape_and_clear_counters (pm);
   pm->current_event++;
   if (pm->current_event >= vec_len (pm->events_to_collect))
     {
       pm->current_event = 0;
       pm->state = PERFMON_STATE_OFF;
       return;
     }
   enable_current_event (pm);

   /* And also on worker threads */
   for (i = 1; i < vec_len (vlib_mains); i++)
     {
       if (vlib_mains[i] == 0)
 	continue;
       vlib_mains[i]->worker_thread_main_loop_callback = (void *)
 	worker_thread_start_event;
     }
 }

 static uword
 perfmon_periodic_process (vlib_main_t * vm,
 			  vlib_node_runtime_t * rt, vlib_frame_t * f)
 {
   perfmon_main_t *pm = &perfmon_main;
   f64 now;
   uword *event_data = 0;
   uword event_type;
   int i;

   while (1)
     {
       if (pm->state == PERFMON_STATE_RUNNING)
 	vlib_process_wait_for_event_or_clock (vm, pm->timeout_interval);
       else
 	vlib_process_wait_for_event (vm);

       now = vlib_time_now (vm);

       event_type = vlib_process_get_events (vm, (uword **) & event_data);

       switch (event_type)
 	{
 	case PERFMON_START:
 	  for (i = 0; i < vec_len (event_data); i++)
 	    start_event (pm, now, event_data[i]);
 	  break;

 	  /* Handle timeout */
 	case ~0:
 	  handle_timeout (pm, now);
 	  break;

 	default:
 	  clib_warning ("Unexpected event %d", event_type);
 	  break;
 	}
       vec_reset_length (event_data);
     }
   return 0;			/* or not */
 }

 /* *INDENT-OFF* */
 VLIB_REGISTER_NODE (perfmon_periodic_node) =
 {
   .function = perfmon_periodic_process,
   .type = VLIB_NODE_TYPE_PROCESS,
   .name = "perfmon-periodic-process",
 };
 /* *INDENT-ON* */

 /*
  * fd.io coding-style-patch-verification: ON
  *
  * Local Variables:
  * eval: (c-set-style "gnu")
  * End:
  */
	/*
	* perfmon_periodic.c - skeleton plug-in periodic function
	*
	* Copyright (c) <current-year> <your-organization>
	* 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.
	*/

	#include <vlib/vlib.h>
	#include <vppinfra/error.h>
	#include <perfmon/perfmon.h>
	#include <asm/unistd.h>
	#include <sys/ioctl.h>

	static long
	perf_event_open (struct perf_event_attr *hw_event, pid_t pid, int cpu,
	int group_fd, unsigned long flags)
	{
	int ret;

	ret = syscall (__NR_perf_event_open, hw_event, pid, cpu, group_fd, flags);
	return ret;
	}

	static u64
	read_current_perf_counter (vlib_main_t * vm)
	{
	if (vm->perf_counter_id)
	return clib_rdpmc (vm->perf_counter_id);
	else
	{
	u64 sw_value;
	if (read (vm->perf_counter_fd, &sw_value, sizeof (sw_value)) !=
	sizeof (sw_value))
	{
	clib_unix_warning ("counter read failed, disable collection...");
	vm->vlib_node_runtime_perf_counter_cb = 0;
	return 0ULL;
	}
	return sw_value;
	}
	}

	static void
	clear_counters (perfmon_main_t * pm)
	{
	int i, j;
	vlib_main_t *vm = pm->vlib_main;
	vlib_main_t *stat_vm;
	vlib_node_main_t *nm;
	vlib_node_t *n;

	vlib_worker_thread_barrier_sync (vm);

	for (j = 0; j < vec_len (vlib_mains); j++)
	{
	stat_vm = vlib_mains[j];
	if (stat_vm == 0)
	continue;

	nm = &stat_vm->node_main;

	/* Clear the node runtime perfmon counters */
	for (i = 0; i < vec_len (nm->nodes); i++)
	{
	n = nm->nodes[i];
	vlib_node_sync_stats (stat_vm, n);
	}

	/* And clear the node perfmon counters */
	for (i = 0; i < vec_len (nm->nodes); i++)
	{
	n = nm->nodes[i];
	n->stats_total.perf_counter_ticks = 0;
	n->stats_total.perf_counter_vectors = 0;
	n->stats_last_clear.perf_counter_ticks = 0;
	n->stats_last_clear.perf_counter_vectors = 0;
	}
	}
	vlib_worker_thread_barrier_release (vm);
	}

	static void
	enable_current_event (perfmon_main_t * pm)
	{
	struct perf_event_attr pe;
	int fd;
	struct perf_event_mmap_page *p = 0;
	perfmon_event_config_t *c;
	vlib_main_t *vm = vlib_get_main ();
	u32 my_thread_index = vm->thread_index;

	c = vec_elt_at_index (pm->events_to_collect, pm->current_event);

	memset (&pe, 0, sizeof (struct perf_event_attr));
	pe.type = c->pe_type;
	pe.size = sizeof (struct perf_event_attr);
	pe.config = c->pe_config;
	pe.disabled = 1;
	pe.pinned = 1;
	/*
	* Note: excluding the kernel makes the
	* (software) context-switch counter read 0...
	*/
	if (pe.type != PERF_TYPE_SOFTWARE)
	{
	/* Exclude kernel and hypervisor */
	pe.exclude_kernel = 1;
	pe.exclude_hv = 1;
	}

	fd = perf_event_open (&pe, 0, -1, -1, 0);
	if (fd == -1)
	{
	clib_unix_warning ("event open: type %d config %d", c->pe_type,
	c->pe_config);
	return;
	}

	if (pe.type != PERF_TYPE_SOFTWARE)
	{
	p = mmap (0, pm->page_size, PROT_READ, MAP_SHARED, fd, 0);
	if (p == MAP_FAILED)
	{
	clib_unix_warning ("mmap");
	close (fd);
	return;
	}
	}

	if (ioctl (fd, PERF_EVENT_IOC_RESET, 0) < 0)
	clib_unix_warning ("reset ioctl");

	if (ioctl (fd, PERF_EVENT_IOC_ENABLE, 0) < 0)
	clib_unix_warning ("enable ioctl");

	/*
	* Software event counters - and others not capable of being
	* read via the "rdpmc" instruction - will be read
	* by system calls.
	*/
	if (pe.type == PERF_TYPE_SOFTWARE \|\| p->cap_user_rdpmc == 0)
	pm->rdpmc_indices[my_thread_index] = 0;
	else /* use rdpmc instrs */
	pm->rdpmc_indices[my_thread_index] = p->index - 1;
	pm->perf_event_pages[my_thread_index] = (void *) p;

	pm->pm_fds[my_thread_index] = fd;

	/* Enable the main loop counter snapshot mechanism */
	vm->perf_counter_id = pm->rdpmc_indices[my_thread_index];
	vm->perf_counter_fd = fd;
	vm->vlib_node_runtime_perf_counter_cb = read_current_perf_counter;
	}

	static void
	disable_event (perfmon_main_t * pm)
	{
	vlib_main_t *vm = vlib_get_main ();
	u32 my_thread_index = vm->thread_index;

	if (pm->pm_fds[my_thread_index] == 0)
	return;

	/* Stop main loop collection */
	vm->vlib_node_runtime_perf_counter_cb = 0;

	if (ioctl (pm->pm_fds[my_thread_index], PERF_EVENT_IOC_DISABLE, 0) < 0)
	clib_unix_warning ("disable ioctl");

	if (pm->perf_event_pages[my_thread_index])
	if (munmap (pm->perf_event_pages[my_thread_index], pm->page_size) < 0)
	clib_unix_warning ("munmap");

	(void) close (pm->pm_fds[my_thread_index]);
	pm->pm_fds[my_thread_index] = 0;
	}

	static void
	worker_thread_start_event (vlib_main_t * vm)
	{
	perfmon_main_t *pm = &perfmon_main;

	enable_current_event (pm);
	vm->worker_thread_main_loop_callback = 0;
	}

	static void
	worker_thread_stop_event (vlib_main_t * vm)
	{
	perfmon_main_t *pm = &perfmon_main;
	disable_event (pm);
	vm->worker_thread_main_loop_callback = 0;
	}

	static void
	start_event (perfmon_main_t * pm, f64 now, uword event_data)
	{
	int i;
	pm->current_event = 0;
	if (vec_len (pm->events_to_collect) == 0)
	{
	pm->state = PERFMON_STATE_OFF;
	return;
	}
	pm->state = PERFMON_STATE_RUNNING;
	clear_counters (pm);

	/* Start collection on this thread */
	enable_current_event (pm);

	/* And also on worker threads */
	for (i = 1; i < vec_len (vlib_mains); i++)
	{
	if (vlib_mains[i] == 0)
	continue;
	vlib_mains[i]->worker_thread_main_loop_callback = (void *)
	worker_thread_start_event;
	}
	}

	void
	scrape_and_clear_counters (perfmon_main_t * pm)
	{
	int i, j;
	vlib_main_t *vm = pm->vlib_main;
	vlib_main_t *stat_vm;
	vlib_node_main_t *nm;
	vlib_node_t ***node_dups = 0;
	vlib_node_t **nodes;
	vlib_node_t *n;
	perfmon_capture_t *c;
	perfmon_event_config_t *current_event;
	uword *p;
	u8 *counter_name;
	u64 counter_value;
	u64 vectors_this_counter;

	/* snapshoot the nodes, including pm counters */
	vlib_worker_thread_barrier_sync (vm);

	for (j = 0; j < vec_len (vlib_mains); j++)
	{
	stat_vm = vlib_mains[j];
	if (stat_vm == 0)
	continue;

	nm = &stat_vm->node_main;

	for (i = 0; i < vec_len (nm->nodes); i++)
	{
	n = nm->nodes[i];
	vlib_node_sync_stats (stat_vm, n);
	}

	nodes = 0;
	vec_validate (nodes, vec_len (nm->nodes) - 1);
	vec_add1 (node_dups, nodes);

	/* Snapshoot and clear the per-node perfmon counters */
	for (i = 0; i < vec_len (nm->nodes); i++)
	{
	n = nm->nodes[i];
	nodes[i] = clib_mem_alloc (sizeof (*n));
	clib_memcpy_fast (nodes[i], n, sizeof (*n));
	n->stats_total.perf_counter_ticks = 0;
	n->stats_total.perf_counter_vectors = 0;
	n->stats_last_clear.perf_counter_ticks = 0;
	n->stats_last_clear.perf_counter_vectors = 0;
	}
	}

	vlib_worker_thread_barrier_release (vm);

	current_event = pm->events_to_collect + pm->current_event;

	for (j = 0; j < vec_len (vlib_mains); j++)
	{
	stat_vm = vlib_mains[j];
	if (stat_vm == 0)
	continue;

	nodes = node_dups[j];

	for (i = 0; i < vec_len (nodes); i++)
	{
	u8 *capture_name;

	n = nodes[i];
	if (n->stats_total.perf_counter_ticks == 0)
	{
	clib_mem_free (n);
	continue;
	}

	capture_name = format (0, "t%d-%v%c", j, n->name, 0);

	p = hash_get_mem (pm->capture_by_thread_and_node_name,
	capture_name);

	if (p == 0)
	{
	pool_get (pm->capture_pool, c);
	memset (c, 0, sizeof (*c));
	c->thread_and_node_name = capture_name;
	hash_set_mem (pm->capture_by_thread_and_node_name,
	capture_name, c - pm->capture_pool);
	}
	else
	c = pool_elt_at_index (pm->capture_pool, p[0]);

	/* Snapshoot counters, etc. into the capture */
	counter_name = (u8 *) current_event->name;
	counter_value = n->stats_total.perf_counter_ticks -
	n->stats_last_clear.perf_counter_ticks;
	vectors_this_counter = n->stats_total.perf_counter_vectors -
	n->stats_last_clear.perf_counter_vectors;

	vec_add1 (c->counter_names, counter_name);
	vec_add1 (c->counter_values, counter_value);
	vec_add1 (c->vectors_this_counter, vectors_this_counter);
	clib_mem_free (n);
	}
	vec_free (nodes);
	}
	vec_free (node_dups);
	}

	static void
	handle_timeout (perfmon_main_t * pm, f64 now)
	{
	int i;
	disable_event (pm);

	/* And also on worker threads */
	for (i = 1; i < vec_len (vlib_mains); i++)
	{
	if (vlib_mains[i] == 0)
	continue;
	vlib_mains[i]->worker_thread_main_loop_callback = (void *)
	worker_thread_stop_event;
	}

	/* Short delay to make sure workers have stopped collection */
	if (i > 1)
	vlib_process_suspend (pm->vlib_main, 1e-3);
	scrape_and_clear_counters (pm);
	pm->current_event++;
	if (pm->current_event >= vec_len (pm->events_to_collect))
	{
	pm->current_event = 0;
	pm->state = PERFMON_STATE_OFF;
	return;
	}
	enable_current_event (pm);

	/* And also on worker threads */
	for (i = 1; i < vec_len (vlib_mains); i++)
	{
	if (vlib_mains[i] == 0)
	continue;
	vlib_mains[i]->worker_thread_main_loop_callback = (void *)
	worker_thread_start_event;
	}
	}

	static uword
	perfmon_periodic_process (vlib_main_t * vm,
	vlib_node_runtime_t * rt, vlib_frame_t * f)
	{
	perfmon_main_t *pm = &perfmon_main;
	f64 now;
	uword *event_data = 0;
	uword event_type;
	int i;

	while (1)
	{
	if (pm->state == PERFMON_STATE_RUNNING)
	vlib_process_wait_for_event_or_clock (vm, pm->timeout_interval);
	else
	vlib_process_wait_for_event (vm);

	now = vlib_time_now (vm);

	event_type = vlib_process_get_events (vm, (uword **) & event_data);

	switch (event_type)
	{
	case PERFMON_START:
	for (i = 0; i < vec_len (event_data); i++)
	start_event (pm, now, event_data[i]);
	break;

	/* Handle timeout */
	case ~0:
	handle_timeout (pm, now);
	break;

	default:
	clib_warning ("Unexpected event %d", event_type);
	break;
	}
	vec_reset_length (event_data);
	}
	return 0; /* or not */
	}

	/* INDENT-OFF */
	VLIB_REGISTER_NODE (perfmon_periodic_node) =
	{
	.function = perfmon_periodic_process,
	.type = VLIB_NODE_TYPE_PROCESS,
	.name = "perfmon-periodic-process",
	};
	/* INDENT-ON */

	/*
	* fd.io coding-style-patch-verification: ON
	*
	* Local Variables:
	* eval: (c-set-style "gnu")
	* End:
	*/