EIT event processing rate configurable

The rate at which EIT events are processed in the backend is limited so that there is always enough processing capacity for the other backend tasks. For many years this limit is set to 20 events per 400 milliseconds. Measuring CPU load on recent hardware shows that mythbackend can process events at a much higher rate without a noticeable increase of CPU load. A higher event procesing rate makes it possible to update the EPG faster. The default value remains at 20 events but the value can now be configured from 20 to 1000 events per 400 milliseconds.
MythTV · Jan 1, 2024 · ee18fbc · ee18fbc
1 parent 90201f0
commit ee18fbc
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Showing 4 changed files with 38 additions and 12 deletions.
diff --git a/mythtv/libs/libmythtv/eithelper.cpp b/mythtv/libs/libmythtv/eithelper.cpp
@@ -21,8 +21,7 @@
 #include "programdata.h"
 #include "scheduledrecording.h"  // for ScheduledRecording
 
-const uint EITHelper::kChunkSize =   20;
-const uint EITHelper::kMaxSize   = 1000;
+const uint EITHelper::kMaxQueueSize   = 10000;
 
 EITCache *EITHelper::s_eitCache = new EITCache();
 
@@ -40,6 +39,13 @@ static void init_fixup(FixupMap &fix);
 EITHelper::EITHelper(uint cardnum) :
     m_cardnum(cardnum)
 {
+    m_chunkSize = gCoreContext->GetNumSetting("EITEventChunkSize", 20);
+    m_queueSize = std::min(m_chunkSize * 50, kMaxQueueSize);
+
+    LOG(VB_EIT, LOG_INFO, LOC_ID +
+        QString("EIThelper chunk size %1 and queue size %2 events")
+            .arg(m_chunkSize).arg(m_queueSize));
+
     // Save EIT cache in database table eit_cache iff true
     bool persistent = gCoreContext->GetBoolSetting("EITCachePersistent", true);
     s_eitCache->SetPersistent(persistent);
@@ -63,7 +69,7 @@ uint EITHelper::GetListSize(void) const
 bool EITHelper::EventQueueFull(void) const
 {
     uint listsize = GetListSize();
-    bool full = listsize > kMaxSize;
+    bool full = listsize > m_queueSize;
     return full;
 }
 
@@ -78,13 +84,15 @@ bool EITHelper::EventQueueFull(void) const
 uint EITHelper::ProcessEvents(void)
 {
     QMutexLocker locker(&m_eitListLock);
-    uint insertCount = 0;
 
     if (m_dbEvents.empty())
         return 0;
 
     MSqlQuery query(MSqlQuery::InitCon());
-    for (uint i = 0; (i < kChunkSize) && (!m_dbEvents.empty()); i++)
+
+    uint eventCount = 0;
+    uint insertCount = 0;
+    for (; (eventCount < m_chunkSize) && (!m_dbEvents.empty()); eventCount++)
     {
         DBEventEIT *event = m_dbEvents.dequeue();
         m_eitListLock.unlock();
@@ -111,7 +119,8 @@ uint EITHelper::ProcessEvents(void)
     else
     {
         LOG(VB_EIT, LOG_INFO, LOC_ID +
-            QString("Added %1 events").arg(insertCount));
+            QString("Added %1/%2 events, queued: %3")
+                .arg(insertCount).arg(eventCount).arg(m_dbEvents.size()));
     }
 
     return insertCount;

diff --git a/mythtv/libs/libmythtv/eithelper.h b/mythtv/libs/libmythtv/eithelper.h
@@ -151,6 +151,8 @@ class EITHelper
     uint                    m_channelid    {0};       // Channel ID
     QDateTime               m_maxStarttime;           // Latest starttime of changed events
     bool                    m_seenEITother {false};   // If false we only reschedule the active mplex
+    uint                    m_chunkSize    {20};      // Maximum number of DB inserts per ProcessEvents call
+    uint                    m_queueSize    {1000};    // Maximum number of events waiting to be processed
 
     FixupMap                m_fixup;
     ATSCSRCToEvents         m_incompleteEvents;
@@ -159,8 +161,7 @@ class EITHelper
 
     QMap<uint,uint>         m_languagePreferences;
 
-    static const uint kChunkSize;   // Maximum number of DB inserts per ProcessEvents call
-    static const uint kMaxSize;     // Maximum number of events waiting to be processed
+    static const uint       kMaxQueueSize;            // Maximum queue size for events waiting to be processed
 };
 
 #endif // EIT_HELPER_H
diff --git a/mythtv/libs/libmythtv/tv_rec.cpp b/mythtv/libs/libmythtv/tv_rec.cpp
@@ -1263,14 +1263,15 @@ V4LChannel *TVRec::GetV4LChannel(void)
 #endif // USING_V4L2
 }
 
+// Check if EIT is enabled for the video source connected to this input
 static bool get_use_eit(uint inputid)
 {
     MSqlQuery query(MSqlQuery::InitCon());
     query.prepare(
         "SELECT SUM(useeit) "
         "FROM videosource, capturecard "
         "WHERE videosource.sourceid = capturecard.sourceid AND"
-        "      capturecard.cardid     = :INPUTID");
+        "      capturecard.cardid   = :INPUTID");
     query.bindValue(":INPUTID", inputid);
 
     if (!query.exec() || !query.isActive())
@@ -1508,7 +1509,7 @@ void TVRec::run(void)
             else if (!get_use_eit(GetInputId()))
             {
                 LOG(VB_EIT, LOG_INFO, LOC +
-                    QString("EIT scanning disabled for all inputs connected to video source %1")
+                    QString("EIT scanning disabled for video source %1")
                         .arg(GetSourceID()));
                 m_eitScanStartTime = MythDate::current().addYears(10);
             }
@@ -4098,8 +4099,8 @@ MPEGStreamData *TVRec::TuningSignalCheck(void)
             else
             {
                 LOG(VB_EIT, LOG_INFO, LOC +
-                    "EIT scanning disabled for all sources on this input.");
-            }
+                    QString("EIT scanning disabled for video source %1")
+                        .arg(GetSourceID()));            }
         }
     }
 

diff --git a/mythtv/programs/mythtv-setup/backendsettings.cpp b/mythtv/programs/mythtv-setup/backendsettings.cpp
@@ -416,6 +416,19 @@ static GlobalSpinBoxSetting *EITScanPeriod()
     return gc;
 }
 
+static GlobalSpinBoxSetting *EITEventChunkSize()
+{
+    auto *gc = new GlobalSpinBoxSetting("EITEventChunkSize", 20, 1000, 20);
+    gc->setLabel(QObject::tr("EIT event chunk size"));
+    gc->setValue(20);
+    QString helpText = QObject::tr(
+        "Maximum number of DB inserts per ProcessEvents call. "
+        "This limits the rate at which EIT events are processed "
+        "in the backend so that there is always enough processing "
+        "capacity for the other backend tasks.");
+    gc->setHelpText(helpText);
+    return gc;
+}
 
 static GlobalCheckBoxSetting *EITCachePersistent()
 {
@@ -430,6 +443,7 @@ static GlobalCheckBoxSetting *EITCachePersistent()
     gc->setHelpText(helpText);
     return gc;
 }
+
 static GlobalSpinBoxSetting *WOLbackendReconnectWaitTime()
 {
     auto *gc = new GlobalSpinBoxSetting("WOLbackendReconnectWaitTime", 0, 1200, 5);
@@ -984,6 +998,7 @@ BackendSettings::BackendSettings()
     group2a1->addChild(EITTransportTimeout());
     group2a1->addChild(EITCrawIdleStart());
     group2a1->addChild(EITScanPeriod());
+    group2a1->addChild(EITEventChunkSize());
     group2a1->addChild(EITCachePersistent());
     addChild(group2a1);