commit 85aa49019f4b4b2b7a4fce4313fdc0f2de65c277
author Dave Barach <dave@barachs.net> Thu Jun 14 18:52:46 2018 -0400
committer Damjan Marion <dmarion@me.com> Thu Jun 21 14:57:02 2018 +0000
tree 14c2ef301403f64e1dd08f7912c86a2cb1bffed3
parent cb3b7052357b57ab927edf178baa1412d7df81d5

configurable per-dispatch-cycle sleep

Workaround for lack of driver interrupt support. Also quite handy for
home gateway, laptop/vagrant, other use-cases not requiring maximum
vectors/second for proper operation.

Change-Id: Ifc4b98112450664beef67b89ab8a6940a3bf24b5
Signed-off-by: Dave Barach <dave@barachs.net>

src/vlib/unix/input.c

diff --git a/src/vlib/unix/input.c b/src/vlib/unix/input.c
index 321e443..0a61c05 100644
--- a/src/vlib/unix/input.c
+++ b/src/vlib/unix/input.c
@@ -148,9 +148,27 @@
     int timeout_ms = 0, max_timeout_ms = 10;
     f64 vector_rate = vlib_last_vectors_per_main_loop (vm);
 
+    /*
+     * If we've been asked for a fixed-sleep between main loop polls,
+     * do so right away.
+     */
+    if (PREDICT_FALSE (is_main && um->poll_sleep_usec))
+      {
+	struct timespec ts, tsrem;
+	timeout = 0;
+	timeout_ms = 0;
+	node->input_main_loops_per_call = 0;
+	ts.tv_sec = 0;
+	ts.tv_nsec = 1000 * um->poll_sleep_usec;
+
+	while (nanosleep (&ts, &tsrem) < 0)
+	  {
+	    ts = tsrem;
+	  }
+      }
     /* If we're not working very hard, decide how long to sleep */
-    if (is_main && vector_rate < 2 && vm->api_queue_nonempty == 0
-	&& nm->input_node_counts_by_state[VLIB_NODE_STATE_POLLING] == 0)
+    else if (is_main && vector_rate < 2 && vm->api_queue_nonempty == 0
+	     && nm->input_node_counts_by_state[VLIB_NODE_STATE_POLLING] == 0)
       {
 	ticks_until_expiration = TW (tw_timer_first_expires_in_ticks)
 	  ((TWT (tw_timer_wheel) *) nm->timing_wheel);

src/vlib/unix/main.c

diff --git a/src/vlib/unix/main.c b/src/vlib/unix/main.c
index 786addf..f812b08 100644
--- a/src/vlib/unix/main.c
+++ b/src/vlib/unix/main.c
@@ -344,6 +344,8 @@
 	um->cli_no_banner = 1;
       else if (unformat (input, "cli-no-pager"))
 	um->cli_no_pager = 1;
+      else if (unformat (input, "poll-sleep-usec %d", &um->poll_sleep_usec))
+	;
       else if (unformat (input, "cli-pager-buffer-limit %d",
 			 &um->cli_pager_buffer_limit))
 	;

src/vlib/unix/unix.h

diff --git a/src/vlib/unix/unix.h b/src/vlib/unix/unix.h
index 4c8566b..7856e5b 100644
--- a/src/vlib/unix/unix.h
+++ b/src/vlib/unix/unix.h
@@ -102,6 +102,9 @@
   /* Store the original state of stdin when it's a tty */
   struct termios tio_stdin;
   int tio_isset;
+
+  u32 poll_sleep_usec;
+
 } unix_main_t;
 
 /* Global main structure. */