Add mixed_mode_algorithm knob

src/base/bittorrent/session.cpp

@@ -283,6 +283,7 @@ Session::Session(QObject *parent)
     , m_maxUploadsPerTorrent(BITTORRENT_SESSION_KEY("MaxUploadsPerTorrent"), -1, lowerLimited(0, -1))
     , m_isUTPEnabled(BITTORRENT_SESSION_KEY("uTPEnabled"), true)
     , m_isUTPRateLimited(BITTORRENT_SESSION_KEY("uTPRateLimited"), true)
+    , m_utpMixedMode(BITTORRENT_SESSION_KEY("uTPMixedMode"), m_isUTPEnabled)
     , m_isAddTrackersEnabled(BITTORRENT_SESSION_KEY("AddTrackersEnabled"), false)
     , m_additionalTrackers(BITTORRENT_SESSION_KEY("AdditionalTrackers"))
     , m_globalMaxRatio(BITTORRENT_SESSION_KEY("GlobalMaxRatio"), -1, [](qreal r) { return r < 0 ? -1. : r;})
@@ -1299,9 +1300,15 @@ void Session::configure(libtorrent::settings_pack &settingsPack)
     // uTP
     settingsPack.set_bool(libt::settings_pack::enable_incoming_utp, isUTPEnabled());
     settingsPack.set_bool(libt::settings_pack::enable_outgoing_utp, isUTPEnabled());
-    settingsPack.set_int(libt::settings_pack::mixed_mode_algorithm, isUTPRateLimited()
-                         ? libt::settings_pack::prefer_tcp
-                         : libt::settings_pack::peer_proportional);
+    switch (utpMixedMode()) {
+    case 0:
+    default:
+        settingsPack.set_int(libt::settings_pack::mixed_mode_algorithm, libt::settings_pack::prefer_tcp);
+        break;
+    case 1:
+        settingsPack.set_int(libt::settings_pack::mixed_mode_algorithm, libt::settings_pack::peer_proportional);
+        break;
+    }
 
     settingsPack.set_bool(libt::settings_pack::apply_ip_filter_to_trackers, isTrackerFilteringEnabled());
 
@@ -1521,9 +1528,15 @@ void Session::configure(libtorrent::session_settings &sessionSettings)
     sessionSettings.enable_outgoing_utp = isUTPEnabled();
     // uTP rate limiting
     sessionSettings.rate_limit_utp = isUTPRateLimited();
-    sessionSettings.mixed_mode_algorithm = isUTPRateLimited()
-                                           ? libt::session_settings::prefer_tcp
-                                           : libt::session_settings::peer_proportional;
+    switch (utpMixedMode()) {
+    case 0:
+    default:
+        sessionSettings.mixed_mode_algorithm = libt::session_settings::prefer_tcp;
+        break;
+    case 1:
+        sessionSettings.mixed_mode_algorithm = libt::session_settings::peer_proportional;
+        break;
+    }
 
     sessionSettings.apply_ip_filter_to_trackers = isTrackerFilteringEnabled();
 
@@ -3090,6 +3103,19 @@ void Session::setUTPRateLimited(bool limited)
     }
 }
 
+int Session::utpMixedMode() const
+{
+    return m_utpMixedMode;
+}
+
+void Session::setUtpMixedMode(int mode)
+{
+    if (mode == m_utpMixedMode) return;
+
+    m_utpMixedMode = mode;
+    configureDeferred();
+}
+
 bool Session::isTrackerFilteringEnabled() const
 {
     return m_isTrackerFilteringEnabled;

src/base/bittorrent/session.h

@@ -373,6 +373,8 @@ namespace BitTorrent
         void setUTPEnabled(bool enabled);
         bool isUTPRateLimited() const;
         void setUTPRateLimited(bool limited);
+        int utpMixedMode() const;
+        void setUtpMixedMode(int mode);
         bool isTrackerFilteringEnabled() const;
         void setTrackerFilteringEnabled(bool enabled);
         QStringList bannedIPs() const;
@@ -597,6 +599,7 @@ namespace BitTorrent
         CachedSettingValue<int> m_maxUploadsPerTorrent;
         CachedSettingValue<bool> m_isUTPEnabled;
         CachedSettingValue<bool> m_isUTPRateLimited;
+        CachedSettingValue<int> m_utpMixedMode;
         CachedSettingValue<bool> m_isAddTrackersEnabled;
         CachedSettingValue<QString> m_additionalTrackers;
         CachedSettingValue<qreal> m_globalMaxRatio;

src/gui/advancedsettings.cpp

@@ -83,6 +83,7 @@ enum AdvSettingsRows
     MAX_HALF_OPEN,
     OUTGOING_PORT_MIN,
     OUTGOING_PORT_MAX,
+    UTP_MIX_MODE,
     // embedded tracker
     TRACKER_STATUS,
     TRACKER_PORT,
@@ -135,6 +136,8 @@ void AdvancedSettings::saveAdvancedSettings()
     // Outgoing ports
     session->setOutgoingPortsMin(outgoing_ports_min.value());
     session->setOutgoingPortsMax(outgoing_ports_max.value());
+    // uTP-TCP mixed mode
+    session->setUtpMixedMode(comboUtpMixedMode.currentIndex());
     // Recheck torrents on completion
     pref->recheckTorrentsOnCompletion(cb_recheck_completed.isChecked());
     // Transfer list refresh interval
@@ -300,6 +303,10 @@ void AdvancedSettings::loadAdvancedSettings()
     outgoing_ports_max.setMaximum(65535);
     outgoing_ports_max.setValue(session->outgoingPortsMax());
     addRow(OUTGOING_PORT_MAX, tr("Outgoing ports (Max) [0: Disabled]"), &outgoing_ports_max);
+    // uTP-TCP mixed mode
+    comboUtpMixedMode.addItems({"Prefer TCP", "Peer proportional (throttles TCP)"});
+    comboUtpMixedMode.setCurrentIndex(session->utpMixedMode());
+    addRow(UTP_MIX_MODE, tr("uTP-TCP mixed mode algorithm"), &comboUtpMixedMode);
     // Recheck completed torrents
     cb_recheck_completed.setChecked(pref->recheckTorrentsOnCompletion());
     addRow(RECHECK_COMPLETED, tr("Recheck torrents on completion"), &cb_recheck_completed);

src/gui/advancedsettings.h

@@ -79,7 +79,7 @@ private:
     QCheckBox cb_os_cache, cb_recheck_completed, cb_resolve_countries, cb_resolve_hosts, cb_super_seeding,
               cb_program_notifications, cb_torrent_added_notifications, cb_tracker_favicon, cb_tracker_status,
               cb_confirm_torrent_recheck, cb_confirm_remove_all_tags, cb_listen_ipv6, cb_announce_all_trackers, cbGuidedReadCache;
-    QComboBox combo_iface, combo_iface_address;
+    QComboBox combo_iface, combo_iface_address, comboUtpMixedMode;
     QLineEdit txtAnnounceIP;
 
     // OS dependent settings