sonic-net · ritvikiscool9 · Jul 20, 2026 · Jul 17, 2026
diff --git a/vppbld/patches/0012-sflow-per-port-sample-rate.patch b/vppbld/patches/0012-sflow-per-port-sample-rate.patch
@@ -0,0 +1,259 @@
+diff --git a/src/plugins/sflow/node.c b/src/plugins/sflow/node.c
+index 3d5363166..3f45c97e2 100644
+--- a/src/plugins/sflow/node.c
++++ b/src/plugins/sflow/node.c
+@@ -73,26 +73,35 @@ sflow_node_ingress_egress (vlib_main_t *vm, vlib_node_runtime_t *node,
+   from = vlib_frame_vector_args (frame);
+   n_left_from = frame->n_vectors;
+
++  u32 dir = (sample_type == SFLOW_SAMPLETYPE_EGRESS) ? VLIB_TX : VLIB_RX;
++  u32 sw_if = vnet_buffer (vlib_get_buffer (vm, from[0]))->sw_if_index[dir];
++  vnet_hw_interface_t *hw = vnet_get_sup_hw_interface(smp->vnet_main, sw_if);
++  sflow_per_interface_data_t *sfif = vec_elt_at_index(smp->per_interface_data, hw->hw_if_index);
++
+   uword thread_index = os_get_thread_index ();
+   sflow_per_thread_data_t *sfwk =
+     vec_elt_at_index (smp->per_thread_data, thread_index);
+
+-  /* note that sfwk->skip==1 means "take the next packet",
+-     so we never see sfwk->skip==0. */
++  /* per-thread, per-interface sampling state: each thread keeps its own
++     skip/pool/seed so concurrent threads on the same interface don't race. */
++  sflow_per_if_sampler_t *smpif =
++    vec_elt_at_index (sfwk->per_interface, hw->hw_if_index);
+
++  /* note that smpif->skip==1 means "take the next packet",
++     so we never see smpif->skip==0. */
+   u32 pkts = n_left_from;
+-  if (PREDICT_TRUE (sfwk->skip > pkts))
++  if (PREDICT_TRUE (smpif->skip > pkts))
+     {
+       /* skip the whole frame-vector */
+-      sfwk->skip -= pkts;
+-      sfwk->pool += pkts;
++      smpif->skip -= pkts;
++      smpif->pool += pkts;
+     }
+   else
+     {
+-      while (pkts >= sfwk->skip)
++      while (pkts >= smpif->skip)
+ 	{
+ 	  /* reach in to get the one we want. */
+-	  vlib_buffer_t *bN = vlib_get_buffer (vm, from[sfwk->skip - 1]);
++	  vlib_buffer_t *bN = vlib_get_buffer (vm, from[smpif->skip - 1]);
+
+ 	  /* Sample this packet header. */
+ 	  u32 hdr = bN->current_length;
+@@ -123,7 +132,7 @@ sflow_node_ingress_egress (vlib_main_t *vm, vlib_node_runtime_t *node,
+
+ 	  sflow_sample_t sample = {
+ 	    .sample_type = sample_type,
+-	    .samplingN = sfwk->smpN,
++	    .samplingN = sfif->samplingN ? sfif->samplingN : smp->samplingN,
+ 	    .input_if_index = if_index,
+ 	    .output_if_index = if_index_out,
+ 	    .sampled_packet_size =
+@@ -151,14 +160,14 @@ sflow_node_ingress_egress (vlib_main_t *vm, vlib_node_runtime_t *node,
+ 	  if (PREDICT_FALSE (!sflow_fifo_enqueue (&sfwk->fifo, &sample)))
+ 	    sfwk->drop++;
+
+-	  pkts -= sfwk->skip;
+-	  sfwk->pool += sfwk->skip;
+-	  sfwk->skip = sflow_next_random_skip (sfwk);
++	  pkts -= smpif->skip;
++	  smpif->pool += smpif->skip;
++	  smpif->skip = sflow_next_random_skip_if (smp, sfif, smpif);
+ 	}
+       /* We took a sample (or several) from this frame-vector, but now we are
+ 	 skipping the rest. */
+-      sfwk->skip -= pkts;
+-      sfwk->pool += pkts;
++      smpif->skip -= pkts;
++      smpif->pool += pkts;
+     }
+
+   /* the rest of this is boilerplate code just to make sure
+diff --git a/src/plugins/sflow/sflow.c b/src/plugins/sflow/sflow.c
+index 89529d1ca..908fbc5e1 100644
+--- a/src/plugins/sflow/sflow.c
++++ b/src/plugins/sflow/sflow.c
+@@ -515,11 +515,13 @@ read_node_counters (sflow_main_t *smp, sflow_err_ctrs_t *ctrs)
+     {
+       sflow_per_thread_data_t *sfwk =
+ 	vec_elt_at_index (smp->per_thread_data, thread_index);
+-      ctrs->counters[SFLOW_ERROR_PROCESSED] += sfwk->pool;
+       ctrs->counters[SFLOW_ERROR_SAMPLED] += sfwk->smpl;
+       ctrs->counters[SFLOW_ERROR_DROPPED] += sfwk->drop;
+       ctrs->counters[SFLOW_ERROR_DIPROCESSED] += sfwk->dsmp;
+       ctrs->counters[SFLOW_ERROR_DIDROPPED] += sfwk->ddrp;
++      /* pool is now tracked per-thread, per-interface */
++      for (int i = 0; i < vec_len (sfwk->per_interface); i++)
++	ctrs->counters[SFLOW_ERROR_PROCESSED] += sfwk->per_interface[i].pool;
+     }
+ }
+
+@@ -641,6 +643,42 @@ sflow_set_worker_sampling_state (sflow_main_t *smp)
+     }
+ }
+
++/* (Re)initialize the per-thread, per-interface sampling state for one
++   interface across all threads.  Called from the control path only (interface
++   enable, per-port or global rate change) so the datapath never races on
++   skip/pool/seed. */
++static void
++sflow_reset_interface_samplers (sflow_main_t *smp, u32 hw_if_index)
++{
++  sflow_per_interface_data_t *sfif =
++    vec_elt_at_index (smp->per_interface_data, hw_if_index);
++  for (clib_thread_index_t thread_index = 0;
++       thread_index < smp->total_threads; thread_index++)
++    {
++      sflow_per_thread_data_t *sfwk =
++	vec_elt_at_index (smp->per_thread_data, thread_index);
++      vec_validate (sfwk->per_interface, hw_if_index);
++      sflow_per_if_sampler_t *smpif =
++	vec_elt_at_index (sfwk->per_interface, hw_if_index);
++      smpif->pool = 0;
++      /* distinct seed per (thread, interface) so threads don't correlate */
++      smpif->seed = hw_if_index ^ (thread_index + 1);
++      smpif->skip = sflow_next_random_skip_if (smp, sfif, smpif);
++    }
++}
++
++static void
++sflow_set_interface_sampling_rate (sflow_main_t *smp)
++{
++  for (int i = 0; i < vec_len (smp->per_interface_data); i++)
++    {
++      sflow_per_interface_data_t *sfif =
++	vec_elt_at_index (smp->per_interface_data, i);
++      if (sfif && sfif->sflow_enabled && !sfif->samplingN)
++	sflow_reset_interface_samplers (smp, i);
++    }
++}
++
+ static void
+ sflow_sampling_start (sflow_main_t *smp)
+ {
+@@ -713,6 +751,7 @@ sflow_sampling_rate (sflow_main_t *smp, u32 samplingN)
+       // dynamic change of sampling rate
+       smp->samplingN = samplingN;
+       sflow_set_worker_sampling_state (smp);
++      sflow_set_interface_sampling_rate (smp);
+     }
+   else
+     {
+@@ -854,14 +893,53 @@ sflow_enable_disable (sflow_main_t *smp, u32 sw_if_index, bool enable_disable)
+       sfif->hw_if_index = sw->hw_if_index;
+       sfif->polled = 0;
+       sfif->sflow_enabled = enable_disable;
++
++      if (enable_disable)
++	{
++	  /* make sure per-thread structures exist, then seed this
++	     interface's per-thread samplers before the feature arc starts
++	     delivering packets to the workers. */
++	  sflow_set_worker_sampling_state (smp);
++	  sflow_reset_interface_samplers (smp, sw->hw_if_index);
++	}
++
+       sflow_enable_disable_interface (smp, sfif);
+       smp->interfacesEnabled += (enable_disable) ? 1 : -1;
+     }
+-
+   sflow_sampling_start_stop (smp);
+   return 0;
+ }
+
++int
++sflow_set_sampling_rate_set (sflow_main_t *smp, u32 sw_if_index, u32 samplingN)
++{
++  vnet_sw_interface_t *sw;
++
++  /* Utterly wrong? */
++  if (pool_is_free_index (smp->vnet_main->interface_main.sw_interfaces,
++			  sw_if_index))
++    return VNET_API_ERROR_INVALID_SW_IF_INDEX;
++
++  /* Not a physical port? */
++  sw = vnet_get_sw_interface (smp->vnet_main, sw_if_index);
++  if (sw->type != VNET_SW_INTERFACE_TYPE_HARDWARE)
++    return VNET_API_ERROR_INVALID_SW_IF_INDEX;
++
++  SFLOW_DBG ("sw_if_index=%u, sup_sw_if_index=%u, hw_if_index=%u\n", sw->sw_if_index, sw->sup_sw_if_index, sw->hw_if_index);
++
++  vec_validate (smp->per_interface_data, sw->hw_if_index);
++  sflow_per_interface_data_t *sfif = vec_elt_at_index (smp->per_interface_data, sw->hw_if_index);
++
++  sfif->samplingN = samplingN;
++  /* re-seed the per-thread samplers for this interface with the new rate.
++     If sampling hasn't started yet the samplers are seeded on enable. */
++  if (smp->total_threads)
++    sflow_reset_interface_samplers (smp, sw->hw_if_index);
++
++  return 0;
++
++}
++
+ static clib_error_t *
+ sflow_sampling_rate_command_fn (vlib_main_t *vm, unformat_input_t *input,
+ 				vlib_cli_command_t *cmd)
+diff --git a/src/plugins/sflow/sflow.h b/src/plugins/sflow/sflow.h
+index 7e8c0469e..cf90d9cea 100644
+--- a/src/plugins/sflow/sflow.h
++++ b/src/plugins/sflow/sflow.h
+@@ -162,6 +162,16 @@ sflow_drop_fifo_dequeue (sflow_drop_fifo_t *fifo, sflow_sample_t *sample)
+   return true;
+ }
+
++/* per-thread, per-interface sampling counters.  Kept per-thread so that
++   multiple worker threads sampling the same interface never share (and race
++   on) skip/pool/seed.  Indexed by hw_if_index. */
++typedef struct
++{
++  u32 skip;
++  u32 pool;
++  u32 seed;
++} sflow_per_if_sampler_t;
++
+ /* private to worker */
+ typedef struct
+ {
+@@ -173,6 +183,8 @@ typedef struct
+   u32 drop;
+   u32 dsmp;
+   u32 ddrp;
++  /* per-interface sampling state, indexed by hw_if_index */
++  sflow_per_if_sampler_t *per_interface;
+   CLIB_CACHE_LINE_ALIGN_MARK (_fifo);
+   sflow_fifo_t fifo;
+   CLIB_CACHE_LINE_ALIGN_MARK (_drop_fifo);
+@@ -246,4 +258,15 @@ sflow_next_random_skip (sflow_per_thread_data_t *sfwk)
+   return (random_u32 (&sfwk->seed) % lim) + 1;
+ }
+
++static inline u32
++sflow_next_random_skip_if (sflow_main_t *smp, sflow_per_interface_data_t *sfif,
++			   sflow_per_if_sampler_t *smpif)
++{
++  u32 effectiveN = sfif->samplingN ? sfif->samplingN : smp->samplingN;
++  if (effectiveN <= 1)
++    return 1;
++  u32 lim = (2 * effectiveN) - 1;
++  return (random_u32 (&smpif->seed) % lim) + 1;
++}
++
+ #endif /* __included_sflow_h__ */
+diff --git a/src/plugins/sflow/sflow_common.h b/src/plugins/sflow/sflow_common.h
+index 3e1021e4a..cd73302a8 100644
+--- a/src/plugins/sflow/sflow_common.h
++++ b/src/plugins/sflow/sflow_common.h
+@@ -19,6 +19,7 @@ typedef struct
+   u32 linux_if_index;
+   u32 polled;
+   int sflow_enabled;
++  u32 samplingN;
+ } sflow_per_interface_data_t;
+
+ /* mirror sflow_direction enum in sflow.api */
diff --git a/vppbld/patches/0013-sflow-per-port-direction.patch b/vppbld/patches/0013-sflow-per-port-direction.patch
@@ -0,0 +1,88 @@
+diff --git a/src/plugins/sflow/sflow.c b/src/plugins/sflow/sflow.c
+index 5b7237c9c..f4283f608 100644
+--- a/src/plugins/sflow/sflow.c
++++ b/src/plugins/sflow/sflow.c
+@@ -792,12 +792,14 @@ void
+ sflow_enable_disable_interface (sflow_main_t *smp,
+ 				sflow_per_interface_data_t *sfif)
+ {
++  u32 direction = sflow_direction_resolve (smp, sfif);
++
+   bool ingress_on =
+-    sfif->sflow_enabled && (smp->samplingD == SFLOW_DIRN_INGRESS ||
+-			    smp->samplingD == SFLOW_DIRN_BOTH);
++    sfif->sflow_enabled && (direction == SFLOW_DIRN_INGRESS ||
++			    direction == SFLOW_DIRN_BOTH);
+   bool egress_on =
+     sfif->sflow_enabled &&
+-    (smp->samplingD == SFLOW_DIRN_EGRESS || smp->samplingD == SFLOW_DIRN_BOTH);
++    (direction == SFLOW_DIRN_EGRESS || direction == SFLOW_DIRN_BOTH);
+   bool drop_on = sfif->sflow_enabled && smp->dropM;
+   bool ingress_enabled = (vnet_feature_is_enabled ("device-input", "sflow",
+ 						   sfif->sw_if_index) == 1);
+@@ -940,6 +942,37 @@ sflow_set_sampling_rate_set (sflow_main_t *smp, u32 sw_if_index, u32 samplingN)
+
+ }
+
++int
++sflow_set_direction_set (sflow_main_t *smp, u32 sw_if_index, u32 direction)
++{
++  vnet_sw_interface_t *sw;
++
++  /* Utterly wrong? */
++  if (pool_is_free_index (smp->vnet_main->interface_main.sw_interfaces,
++			  sw_if_index))
++    return VNET_API_ERROR_INVALID_SW_IF_INDEX;
++
++  /* Not a physical port? */
++  sw = vnet_get_sw_interface (smp->vnet_main, sw_if_index);
++  if (sw->type != VNET_SW_INTERFACE_TYPE_HARDWARE)
++    return VNET_API_ERROR_INVALID_SW_IF_INDEX;
++
++  if (direction > SFLOW_DIRN_BOTH)
++    return VNET_API_ERROR_INVALID_VALUE;
++
++  SFLOW_DBG ("sw_if_index=%u, sup_sw_if_index=%u, hw_if_index=%u\n",
++	     sw->sw_if_index, sw->sup_sw_if_index, sw->hw_if_index);
++
++  vec_validate (smp->per_interface_data, sw->hw_if_index);
++  sflow_per_interface_data_t *sfif =
++    vec_elt_at_index (smp->per_interface_data, sw->hw_if_index);
++
++  sfif->direction = direction;
++  sflow_enable_disable_interface (smp, sfif);
++
++  return 0;
++}
++
+ static clib_error_t *
+ sflow_sampling_rate_command_fn (vlib_main_t *vm, unformat_input_t *input,
+ 				vlib_cli_command_t *cmd)
+diff --git a/src/plugins/sflow/sflow.h b/src/plugins/sflow/sflow.h
+index cf90d9cea..e26896b1a 100644
+--- a/src/plugins/sflow/sflow.h
++++ b/src/plugins/sflow/sflow.h
+@@ -269,4 +269,11 @@ sflow_next_random_skip_if (sflow_main_t *smp, sflow_per_interface_data_t *sfif,
+   return (random_u32 (&smpif->seed) % lim) + 1;
+ }
+
++static inline u32
++sflow_direction_resolve (sflow_main_t *smp, sflow_per_interface_data_t *sfif)
++{
++  u32 effectiveD = sfif->direction ? sfif->direction : smp->samplingD;
++  return effectiveD;
++}
++
+ #endif /* __included_sflow_h__ */
+diff --git a/src/plugins/sflow/sflow_common.h b/src/plugins/sflow/sflow_common.h
+index cd73302a8..6055d04f1 100644
+--- a/src/plugins/sflow/sflow_common.h
++++ b/src/plugins/sflow/sflow_common.h
+@@ -20,6 +20,7 @@ typedef struct
+   u32 polled;
+   int sflow_enabled;
+   u32 samplingN;
++  u32 direction;
+ } sflow_per_interface_data_t;
+
+ /* mirror sflow_direction enum in sflow.api */