ofproto: Report controller rate limiting statistics in database.

Signed-off-by: Ben Pfaff <blp@nicira.com>
Acked-by: Gurucharan Shetty <gshetty@nicira.com>

NEWS

@@ -7,6 +7,7 @@ Post-v2.3.0
      possible to generate or match options. This is planned for a future
      release. The protocol is documented at
      http://tools.ietf.org/html/draft-gross-geneve-00
+   - The OVS database now reports controller rate limiting statistics.
 
 
 v2.3.0 - xx xxx xxxx

ofproto/connmgr.c

@@ -414,7 +414,10 @@ connmgr_get_memory_usage(const struct connmgr *mgr, struct simap *usage)
 
         packets += rconn_count_txqlen(ofconn->rconn);
         for (i = 0; i < N_SCHEDULERS; i++) {
-            packets += pinsched_count_txqlen(ofconn->schedulers[i]);
+            struct pinsched_stats stats;
+
+            pinsched_get_stats(ofconn->schedulers[i], &stats);
+            packets += stats.n_queued;;
         }
         packets += pktbuf_count_packets(ofconn->pktbuf);
     }
@@ -471,6 +474,7 @@ connmgr_get_controller_info(struct connmgr *mgr, struct shash *info)
             time_t last_connection = rconn_get_last_connection(rconn);
             time_t last_disconnect = rconn_get_last_disconnect(rconn);
             int last_error = rconn_get_last_error(rconn);
+            int i;
 
             shash_add(info, target, cinfo);
 
@@ -494,6 +498,27 @@ connmgr_get_controller_info(struct connmgr *mgr, struct shash *info)
                 smap_add_format(&cinfo->pairs, "sec_since_disconnect",
                                 "%ld", (long int) (now - last_disconnect));
             }
+
+            for (i = 0; i < N_SCHEDULERS; i++) {
+                if (ofconn->schedulers[i]) {
+                    const char *name = i ? "miss" : "action";
+                    struct pinsched_stats stats;
+
+                    pinsched_get_stats(ofconn->schedulers[i], &stats);
+                    smap_add_nocopy(&cinfo->pairs,
+                                    xasprintf("packet-in-%s-backlog", name),
+                                    xasprintf("%u", stats.n_queued));
+                    smap_add_nocopy(&cinfo->pairs,
+                                    xasprintf("packet-in-%s-bypassed", name),
+                                    xasprintf("%llu", stats.n_normal));
+                    smap_add_nocopy(&cinfo->pairs,
+                                    xasprintf("packet-in-%s-queued", name),
+                                    xasprintf("%llu", stats.n_limited));
+                    smap_add_nocopy(&cinfo->pairs,
+                                    xasprintf("packet-in-%s-dropped", name),
+                                    xasprintf("%llu", stats.n_queue_dropped));
+                }
+            }
         }
     }
 }

ofproto/pinsched.c

@@ -295,10 +295,17 @@ pinsched_set_limits(struct pinsched *ps, int rate_limit, int burst_limit)
     }
 }
 
-/* Returns the number of packets scheduled to be sent eventually by 'ps'.
+/* Retrieves statistics for 'ps'.  The statistics will be all zero if 'ps' is
- * Returns 0 if 'ps' is null. */
+ * null. */
-unsigned int
+void
-pinsched_count_txqlen(const struct pinsched *ps)
+pinsched_get_stats(const struct pinsched *ps, struct pinsched_stats *stats)
 {
-    return ps ? ps->n_queued : 0;
+    if (ps) {
+        stats->n_queued = ps->n_queued;
+        stats->n_normal = ps->n_normal;
+        stats->n_limited = ps->n_limited;
+        stats->n_queue_dropped = ps->n_queue_dropped;
+    } else {
+        memset(stats, 0, sizeof *stats);
+    }
 }

ofproto/pinsched.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013 Nicira, Inc.
+ * Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013, 2014 Nicira, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -33,6 +33,13 @@ void pinsched_send(struct pinsched *, ofp_port_t port_no, struct ofpbuf *,
 void pinsched_run(struct pinsched *, struct list *txq);
 void pinsched_wait(struct pinsched *);
 
-unsigned int pinsched_count_txqlen(const struct pinsched *);
+struct pinsched_stats {
+    unsigned int n_queued;              /* # currently queued to send. */
+    unsigned long long n_normal;        /* # txed w/o rate limit queuing. */
+    unsigned long long n_limited;       /* # queued for rate limiting. */
+    unsigned long long n_queue_dropped; /* # dropped due to queue overflow. */
+};
+
+void pinsched_get_stats(const struct pinsched *, struct pinsched_stats *);
 
 #endif /* pinsched.h */

vswitchd/vswitch.xml

@@ -3223,7 +3223,7 @@
       </column>
     </group>
 
-    <group title="Asynchronous Message Configuration">
+    <group title="Asynchronous Messages">
       <p>
         OpenFlow switches send certain messages to controllers spontanenously,
         that is, not in response to any request from the controller.  These
@@ -3243,38 +3243,102 @@
         on any messages that it does want to receive, if any.
       </column>
 
-      <column name="controller_rate_limit">
+      <group title="Controller Rate Limiting">
         <p>
-          The maximum rate at which the switch will forward packets to the
+          A switch can forward packets to a controller over the OpenFlow
-          OpenFlow controller, in packets per second.  This feature prevents a
+          protocol.  Forwarding packets this way at too high a rate can
-          single bridge from overwhelming the controller.  If not specified,
+          overwhelm a controller, frustrate use of the OpenFlow connection for
-          the default is implementation-specific.
+          other purposes, increase the latency of flow setup, and use an
+          unreasonable amount of bandwidth.  Therefore, Open vSwitch supports
+          limiting the rate of packet forwarding to a controller.
         </p>
 
         <p>
-          In addition, when a high rate triggers rate-limiting, Open vSwitch
+          There are two main reasons in OpenFlow for a packet to be sent to a
-          queues controller packets for each port and transmits them to the
+          controller: either the packet ``misses'' in the flow table, that is,
-          controller at the configured rate.  The <ref
+          there is no matching flow, or a flow table action says to send the
-          column="controller_burst_limit"/> value limits the number of queued
+          packet to the controller.  Open vSwitch limits the rate of each kind
-          packets.  Ports on a bridge share the packet queue fairly.
+          of packet separately at the configured rate.  Therefore, the actual
+          rate that packets are sent to the controller can be up to twice the
+          configured rate, when packets are sent for both reasons.
         </p>
 
         <p>
-          Open vSwitch maintains two such packet rate-limiters per bridge: one
+          This feature is specific to forwarding packets over an OpenFlow
-          for packets sent up to the controller because they do not correspond
+          connection.  It is not general-purpose QoS.  See the <ref
-          to any flow, and the other for packets sent up to the controller by
+          table="QoS"/> table for quality of service configuration, and <ref
-          request through flow actions. When both rate-limiters are filled with
+          column="ingress_policing_rate" table="Interface"/> in the <ref
-          packets, the actual rate that packets are sent to the controller is
+          table="Interface"/> table for ingress policing configuration.
-          up to twice the specified rate.
         </p>
-      </column>
 
-      <column name="controller_burst_limit">
+        <column name="controller_rate_limit">
-        In conjunction with <ref column="controller_rate_limit"/>,
+          <p>
-        the maximum number of unused packet credits that the bridge will
+            The maximum rate at which the switch will forward packets to the
-        allow to accumulate, in packets.  If not specified, the default
+            OpenFlow controller, in packets per second.  If no value is
-        is implementation-specific.
+            specified, rate limiting is disabled.
-      </column>
+          </p>
+        </column>
+
+        <column name="controller_burst_limit">
+          <p>
+            When a high rate triggers rate-limiting, Open vSwitch queues
+            packets to the controller for each port and transmits them to the
+            controller at the configured rate.  This value limits the number of
+            queued packets.  Ports on a bridge share the packet queue fairly.
+          </p>
+
+          <p>
+            This value has no effect unless <ref
+            column="controller_rate_limit"/> is configured.  The current
+            default when this value is not specified is one-quarter of <ref
+            column="controller_rate_limit"/>, meaning that queuing can delay
+            forwarding a packet to the controller by up to 250 ms.
+          </p>
+        </column>
+
+        <group title="Controller Rate Limiting Statistics">
+          <p>
+            These values report the effects of rate limiting.  Their values are
+            relative to establishment of the most recent OpenFlow connection,
+            or since rate limiting was enabled, whichever happened more
+            recently.  Each consists of two values, one with <code>TYPE</code>
+            replaced by <code>miss</code> for rate limiting flow table misses,
+            and the other with <code>TYPE</code> replaced by
+            <code>action</code> for rate limiting packets sent by OpenFlow
+            actions.
+          </p>
+
+          <p>
+            These statistics are reported only when controller rate limiting is
+            enabled.
+          </p>
+
+          <column name="status" key="packet-in-TYPE-bypassed"
+                  type='{"type": "integer", "minInteger": 0}'>
+            Number of packets sent directly to the controller, without queuing,
+            because the rate did not exceed the configured maximum.
+          </column>
+
+          <column name="status" key="packet-in-TYPE-queued"
+                  type='{"type": "integer", "minInteger": 0}'>
+            Number of packets added to the queue to send later.
+          </column>
+
+          <column name="status" key="packet-in-TYPE-dropped"
+                  type='{"type": "integer", "minInteger": 0}'>
+            Number of packets added to the queue that were later dropped due to
+            overflow.  This value is less than or equal to <ref column="status"
+            key="packet-in-TYPE-queued"/>.
+          </column>
+
+          <column name="status" key="packet-in-TYPE-backlog"
+                  type='{"type": "integer", "minInteger": 0}'>
+            Number of packets currently queued.  The other statistics increase
+            monotonically, but this one fluctuates between 0 and the <ref
+            column="controller_burst_limit"/> as conditions change.
+          </column>
+        </group>
+      </group>
     </group>
 
     <group title="Additional In-Band Configuration">