dpdk: register rte_delay_us callback from vnet

Change-Id: Ibf7fc9a54d3fbee431b4814fa8abc5ba29ed9eef
Signed-off-by: Damjan Marion <damarion@cisco.com>

1 files changed, 90 insertions, 0 deletions

diff --git a/src/vnet/devices/dpdk/main.c b/src/vnet/devices/dpdk/main.c
new file mode 100644
index 00000000000..1e6ec2f892f
--- /dev/null
+++ b/src/vnet/devices/dpdk/main.c
@@ -0,0 +1,90 @@
+/*
+ * Copyright (c) 2017 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.
+ */
+
+#include <vnet/vnet.h>
+#include <vnet/devices/dpdk/dpdk.h>
+
+
+/*
+ * Called by the dpdk driver's rte_delay_us() function.
+ * Return 0 to have the dpdk do a regular delay loop.
+ * Return 1 if to skip the delay loop because we are suspending
+ * the calling vlib process instead.
+ */
+int
+rte_delay_us_override (unsigned us)
+{
+  vlib_main_t *vm;
+
+  /* Don't bother intercepting for short delays */
+  if (us < 10)
+    return 0;
+
+  /*
+   * Only intercept if we are in a vlib process.
+   * If we are called from a vlib worker thread or the vlib main
+   * thread then do not intercept. (Must not be called from an
+   * independent pthread).
+   */
+  if (os_get_cpu_number () == 0)
+    {
+      /*
+       * We're in the vlib main thread or a vlib process. Make sure
+       * the process is running and we're not still initializing.
+       */
+      vm = vlib_get_main ();
+      if (vlib_in_process_context (vm))
+	{
+	  /* Only suspend for the admin_down_process */
+	  vlib_process_t *proc = vlib_get_current_process (vm);
+	  if (!(proc->flags & VLIB_PROCESS_IS_RUNNING) ||
+	      (proc->node_runtime.function != admin_up_down_process))
+	    return 0;
+
+	  f64 delay = 1e-6 * us;
+	  vlib_process_suspend (vm, delay);
+	  return 1;
+	}
+    }
+  return 0;			// no override
+}
+
+#if RTE_VERSION >= RTE_VERSION_NUM(16, 11, 0, 0)
+static void
+rte_delay_us_override_cb (unsigned us)
+{
+  if (rte_delay_us_override (us) == 0)
+    rte_delay_us_block (us);
+}
+#endif
+
+static clib_error_t * dpdk_main_init (vlib_main_t * vm)
+{
+  clib_error_t * error = 0;
+
+  if ((error = vlib_call_init_function (vm, dpdk_init)))
+    return error;
+
+#if DPDK
+#if RTE_VERSION >= RTE_VERSION_NUM(16, 11, 0, 0)
+  /* register custom delay function */
+  rte_delay_us_callback_register (rte_delay_us_override_cb);
+#endif
+#endif
+  return error;
+}
+
+VLIB_INIT_FUNCTION (dpdk_main_init);
+