Calculate per stream jitter using latency values

We calculate "average jitter".

The changes include only the server side, not the client/GUI side which will
be done in a future commit.

common/protocol.proto

@@ -293,6 +293,7 @@ message StreamStats {
 
     optional double tx_duration = 3; // in seconds
     optional uint64 latency = 4;     // in nanoseconds
+    optional uint64 jitter = 5;      // in nanoseconds
 
     optional uint64 rx_pkts = 11;
     optional uint64 rx_bytes = 12;

server/abstractport.cpp

@@ -26,7 +26,6 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>
 #include "devicemanager.h"
 #include "interfaceinfo.h"
 #include "packetbuffer.h"
-#include "streamtiming.h"
 
 #include <QString>
 #include <QIODevice>
@@ -886,9 +885,9 @@ void AbstractPort::stats(PortStats *stats)
                         stats_.rxFrameErrors + (maxStatsValue_ - epochStats_.rxFrameErrors);
 }
 
-quint64 AbstractPort::streamTimingDelay(uint guid)
+StreamTiming::Stats AbstractPort::streamTimingStats(uint guid)
 {
-    return streamTiming_->delay(id(), guid);
+    return streamTiming_->stats(id(), guid);
 }
 
 void AbstractPort::clearStreamTiming(uint guid)
@@ -909,12 +908,14 @@ void AbstractPort::streamStats(uint guid, OstProto::StreamStatsList *stats)
     {
         StreamStatsTuple sst = streamStats_.value(guid);
         OstProto::StreamStats *s = stats->add_stream_stats();
+        StreamTiming::Stats t = streamTimingStats(guid);
 
         s->mutable_stream_guid()->set_id(guid);
         s->mutable_port_id()->set_id(id());
 
         s->set_tx_duration(lastTransmitDuration());
-        s->set_latency(streamTimingDelay(guid));
+        s->set_latency(t.latency);
+        s->set_jitter(t.jitter);
 
         s->set_tx_pkts(sst.tx_pkts);
         s->set_tx_bytes(sst.tx_bytes);
@@ -941,12 +942,14 @@ void AbstractPort::streamStatsAll(OstProto::StreamStatsList *stats)
         i.next();
         StreamStatsTuple sst = i.value();
         OstProto::StreamStats *s = stats->add_stream_stats();
+        StreamTiming::Stats t = streamTimingStats(i.key());
 
         s->mutable_stream_guid()->set_id(i.key());
         s->mutable_port_id()->set_id(id());
 
         s->set_tx_duration(txDur);
-        s->set_latency(streamTimingDelay(i.key()));
+        s->set_latency(t.latency);
+        s->set_jitter(t.jitter);
 
         s->set_tx_pkts(sst.tx_pkts);
         s->set_tx_bytes(sst.tx_bytes);

server/abstractport.h

@@ -22,6 +22,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>
 
 #include "../common/protocol.pb.h"
 #include "streamstats.h"
+#include "streamtiming.h"
 
 #include <QList>
 #include <QReadWriteLock>
@@ -34,7 +35,6 @@ struct InterfaceInfo;
 class PacketBuffer;
 class QIODevice;
 class StreamBase;
-class StreamTiming;
 
 // TODO: send notification back to client(s)
 #define Xnotify qWarning
@@ -125,7 +125,7 @@ public:
     void stats(PortStats *stats);
     void resetStats() { epochStats_ = stats_; }
 
-    quint64 streamTimingDelay(uint guid);
+    StreamTiming::Stats streamTimingStats(uint guid);
     void clearStreamTiming(uint guid = UINT_MAX);
 
     // FIXME: combine single and All calls?

server/streamtiming.cpp

@@ -62,8 +62,10 @@ void StreamTiming::stop(uint portId)
     }
 }
 
-quint64 StreamTiming::delay(uint portId, uint guid)
+StreamTiming::Stats StreamTiming::stats(uint portId, uint guid)
 {
+    Stats stats = {0, 0};
+
     Q_ASSERT(guid <= SignProtocol::kMaxGuid);
 
     // Process anything pending first
@@ -72,13 +74,16 @@ quint64 StreamTiming::delay(uint portId, uint guid)
     QMutexLocker locker(&timingLock_);
 
     if (!timing_.contains(portId))
-        return 0;
+        return stats;
 
     Timing t = timing_.value(portId)->value(guid);
     if (t.countDelays == 0)
-        return 0;
+        return stats;
 
-    return timespecToNsecs(t.sumDelays)/t.countDelays;
+    stats.latency = timespecToNsecs(t.sumDelays)/t.countDelays;
+    stats.jitter = t.sumJitter/(t.countDelays-1);
+
+    return stats;
 }
 
 void StreamTiming::clear(uint portId, uint guid)
@@ -127,6 +132,12 @@ int StreamTiming::processRecords()
             PortTiming *portTiming = timing_.value(portId);
             Timing &guidTiming = (*portTiming)[guid];
             timespecadd(&guidTiming.sumDelays, &diff, &guidTiming.sumDelays);
+            if (guidTiming.countDelays)
+                guidTiming.sumJitter += abs(
+                        diff.tv_sec*long(1e9) + diff.tv_nsec
+                        - guidTiming.lastDelay.tv_sec*long(1e9)
+                        - guidTiming.lastDelay.tv_nsec);
+            guidTiming.lastDelay = diff;
             guidTiming.countDelays++;
 
             count++;
@@ -136,10 +147,10 @@ int StreamTiming::processRecords()
                 diff.tv_sec, diff.tv_nsec,
                 rxTime.tv_sec, rxTime.tv_nsec,
                 txTime.tv_sec, txTime.tv_nsec);
-            timingDebug("[%u/%u](%d) total %ld.%09ld count %u",
+            timingDebug("[%u/%u](%d) total %ld.%09ld count %u jittersum %09llu",
                 i.value().portId, guid, count,
                 guidTiming.sumDelays.tv_sec, guidTiming.sumDelays.tv_nsec,
-                guidTiming.countDelays);
+                guidTiming.countDelays, guidTiming.sumJitter);
         }
         i = rxHash_.erase(i);
     }

server/streamtiming.h

@@ -34,6 +34,12 @@ class StreamTiming : public QObject
 {
     Q_OBJECT
 public:
+    struct Stats
+    {
+        quint64 latency;
+        quint64 jitter;
+    };
+
     bool recordTxTime(uint portId, uint guid, uint ttagId,
                       const struct timespec &timestamp);
     bool recordRxTime(uint portId, uint guid, uint ttagId,
@@ -47,7 +53,7 @@ public:
     bool recordTxTime(uint portId, uint *ttagList, int count,
                       const struct timespec &timestamp);
 
-    quint64 delay(uint portId, uint guid);
+    Stats stats(uint portId, uint guid);
     void clear(uint portId, uint guid = SignProtocol::kInvalidGuid);
 
     static StreamTiming* instance();
@@ -72,8 +78,13 @@ private:
         uint portId;
     };
 
+    // XXX: used only as a Qt Container value, so members will get init to 0
+    // when this struct is retrieved from the container due to Qt's default-
+    // cosntructed value semantics
     struct Timing {
         struct timespec sumDelays; // nanosec resolution
+        struct timespec lastDelay;
+        quint64 sumJitter; // nanosec resolution
         uint countDelays;
     };