vcl: use events for epoll/select/read/write

Have vcl poll and wait on the event message queues as opposed to
constantly polling the session fifos. This also adds event signaling to
cut through sessions.

On the downside, because we can't wait on multiple condvars, i.e., when
we have multiple message queues because of cut-through registrations, we
do timed waits.

Change-Id: I29ade95dba449659fe46008bb1af502276a7c5fd
Signed-off-by: Florin Coras <fcoras@cisco.com>

1 files changed, 32 insertions, 6 deletions

diff --git a/src/svm/message_queue.h b/src/svm/message_queue.h
index e4a5f07d480..4c16c97ca7c 100644
--- a/src/svm/message_queue.h
+++ b/src/svm/message_queue.h
@@ -22,6 +22,7 @@
 
 #include <vppinfra/clib.h>
 #include <vppinfra/error.h>
+#include <vppinfra/time.h>
 #include <svm/queue.h>
 
 typedef struct svm_msg_q_ring_
@@ -274,12 +275,6 @@ svm_msg_q_lock (svm_msg_q_t * mq)
   return pthread_mutex_lock (&mq->q->mutex);
 }
 
-static inline void
-svm_msg_q_wait (svm_msg_q_t * mq)
-{
-  pthread_cond_wait (&mq->q->condvar, &mq->q->mutex);
-}
-
 /**
  * Unlock message queue
  */
@@ -292,6 +287,37 @@ svm_msg_q_unlock (svm_msg_q_t * mq)
   pthread_mutex_unlock (&mq->q->mutex);
 }
 
+/**
+ * Wait for message queue event
+ *
+ * Must be called with mutex held
+ */
+static inline void
+svm_msg_q_wait (svm_msg_q_t * mq)
+{
+  pthread_cond_wait (&mq->q->condvar, &mq->q->mutex);
+}
+
+/**
+ * Timed wait for message queue event
+ *
+ * Must be called with mutex held.
+ *
+ * @param mq 		message queue
+ * @param timeout	time in seconds
+ */
+static inline int
+svm_msg_q_timedwait (svm_msg_q_t * mq, double timeout)
+{
+  struct timespec ts;
+
+  ts.tv_sec = unix_time_now () + (u32) timeout;
+  ts.tv_nsec = (timeout - (u32) timeout) * 1e9;
+  if (pthread_cond_timedwait (&mq->q->condvar, &mq->q->mutex, &ts))
+    return -1;
+  return 0;
+}
+
 #endif /* SRC_SVM_MESSAGE_QUEUE_H_ */
 
 /*