linux-cp: add support for tap num queues config

This change allows to limit lcp interface queues
to be used by explicit host interface workers.

Type: improvement
Signed-off-by: Vladislav Grishenko <themiron@yandex-team.ru>
Change-Id: I0626f66021e5a5f251470156231dc44ddaea5ee6

3 files changed, 39 insertions, 2 deletions

diff --git a/src/plugins/linux-cp/lcp.c b/src/plugins/linux-cp/lcp.c
index 561ebb152ae..34e8550a13f 100644
--- a/src/plugins/linux-cp/lcp.c
+++ b/src/plugins/linux-cp/lcp.c
@@ -161,6 +161,28 @@ lcp_get_netlink_processing_active (void)
   return lcpm->netlink_processing_active;
 }
 
+void
+lcp_set_default_num_queues (u16 num_queues, u8 is_tx)
+{
+  lcp_main_t *lcpm = &lcp_main;
+
+  if (is_tx)
+    lcpm->num_tx_queues = num_queues;
+  else
+    lcpm->num_rx_queues = num_queues;
+}
+
+u16
+lcp_get_default_num_queues (u8 is_tx)
+{
+  lcp_main_t *lcpm = &lcp_main;
+
+  if (is_tx)
+    return lcpm->num_tx_queues;
+
+  return lcpm->num_rx_queues ?: vlib_num_workers ();
+}
+
 /*
  * fd.io coding-style-patch-verification: ON
  *
diff --git a/src/plugins/linux-cp/lcp.h b/src/plugins/linux-cp/lcp.h
index 3b6b4ec00d4..e89b149f67d 100644
--- a/src/plugins/linux-cp/lcp.h
+++ b/src/plugins/linux-cp/lcp.h
@@ -28,6 +28,8 @@ typedef struct lcp_main_s
   u8 lcp_sync;	      /* Automatically sync VPP changes to LCP */
   u8 del_static_on_link_down;  /* Delete static routes when link goes down */
   u8 del_dynamic_on_link_down; /* Delete dynamic routes when link goes down */
+  u16 num_rx_queues;
+  u16 num_tx_queues;
   u8 test_mode;	      /* Set when Unit testing */
   u8 netlink_processing_active; /* Set while a batch of Netlink messages are
 				   being processed */
@@ -61,6 +63,12 @@ u8 lcp_get_del_dynamic_on_link_down (void);
 void lcp_set_netlink_processing_active (u8 is_processing);
 u8 lcp_get_netlink_processing_active (void);
 
+/**
+ * Get/Set the default queue number for LCP host taps.
+ */
+void lcp_set_default_num_queues (u16 num_queues, u8 is_tx);
+u16 lcp_get_default_num_queues (u8 is_tx);
+
 #endif
 
 /*
diff --git a/src/plugins/linux-cp/lcp_interface.c b/src/plugins/linux-cp/lcp_interface.c
index 921dccf5519..e1f4a6a1d69 100644
--- a/src/plugins/linux-cp/lcp_interface.c
+++ b/src/plugins/linux-cp/lcp_interface.c
@@ -555,6 +555,7 @@ static clib_error_t *
 lcp_itf_pair_config (vlib_main_t *vm, unformat_input_t *input)
 {
   u8 *default_ns;
+  u32 tmp;
 
   default_ns = NULL;
 
@@ -579,6 +580,10 @@ lcp_itf_pair_config (vlib_main_t *vm, unformat_input_t *input)
 	lcp_set_del_static_on_link_down (1 /* is_del */);
       else if (unformat (input, "del-dynamic-on-link-down"))
 	lcp_set_del_dynamic_on_link_down (1 /* is_del */);
+      else if (unformat (input, "num-rx-queues %d", &tmp))
+	lcp_set_default_num_queues (tmp, 0 /* is_tx */);
+      else if (unformat (input, "num-tx-queues %d", &tmp))
+	lcp_set_default_num_queues (tmp, 1 /* is_tx */);
       else
 	return clib_error_return (0, "interfaces not found");
     }
@@ -988,8 +993,10 @@ lcp_itf_pair_create (u32 phy_sw_if_index, u8 *host_if_name,
   else
     {
       tap_create_if_args_t args = {
-	.num_rx_queues = clib_max (1, vlib_num_workers ()),
-	.num_tx_queues = 1,
+	.num_rx_queues =
+	  clib_max (1, lcp_get_default_num_queues (0 /* is_tx */)),
+	.num_tx_queues =
+	  clib_max (1, lcp_get_default_num_queues (1 /* is_tx */)),
 	.id = hw->hw_if_index,
 	.sw_if_index = ~0,
 	.rx_ring_sz = 256,