support for enabling delay based dropping threshold

Summary:
As titled, add support for enabling delay based dropping congestion threshold in FBOSS.

NOTE that this diff is a no-op since the attribute is not used yet. I will follow up with another diff for setting the attribute.

Differential Revision: D61602331

fbshipit-source-id: b3e8aebcd083891451d143fdf791dabe48f9e106

fboss/agent/hw/sai/api/SwitchApi.h

@@ -420,6 +420,11 @@ struct SaiSwitchTraits {
     };
     using RestartIssu =
         SaiExtensionAttribute<bool, AttributeRestartIssuWrapper>;
+    struct AttributeDelayDropCongThreshold {
+      std::optional<sai_attr_id_t> operator()();
+    };
+    using DelayDropCongThreshold =
+        SaiExtensionAttribute<sai_uint8_t, AttributeDelayDropCongThreshold>;
     struct AttributeForceTrafficOverFabricWrapper {
       std::optional<sai_attr_id_t> operator()();
     };
@@ -614,7 +619,8 @@ struct SaiSwitchTraits {
       ,
       std::optional<Attributes::ArsProfile>
 #endif
-      >;
+      ,
+      std::optional<Attributes::DelayDropCongThreshold>>;
 
 #if SAI_API_VERSION >= SAI_VERSION(1, 12, 0)
   static constexpr std::array<sai_stat_id_t, 3> CounterIdsToRead = {
@@ -721,6 +727,7 @@ SAI_ATTRIBUTE_NAME(Switch, EcmpMemberCount)
 #endif
 SAI_ATTRIBUTE_NAME(Switch, DllPath)
 SAI_ATTRIBUTE_NAME(Switch, RestartIssu)
+SAI_ATTRIBUTE_NAME(Switch, DelayDropCongThreshold)
 SAI_ATTRIBUTE_NAME(Switch, ForceTrafficOverFabric)
 SAI_ATTRIBUTE_NAME(Switch, WarmBootTargetVersion)
 SAI_ATTRIBUTE_NAME(Switch, SwitchIsolate)

fboss/agent/hw/sai/api/bcm/SwitchApi.cpp

@@ -184,6 +184,11 @@ void SwitchApi::registerSwitchEventCallback(
 #endif
 }
 
+std::optional<sai_attr_id_t>
+SaiSwitchTraits::Attributes::AttributeDelayDropCongThreshold::operator()() {
+  return std::nullopt;
+}
+
 std::optional<sai_attr_id_t> SaiSwitchTraits::Attributes::
     AttributeForceTrafficOverFabricWrapper::operator()() {
 #if defined(BRCM_SAI_SDK_DNX)

fboss/agent/hw/sai/api/fake/FakeSaiExtensions.cpp

@@ -130,6 +130,11 @@ SaiSwitchTraits::Attributes::AttributeRestartIssuWrapper::operator()() {
   return SAI_SWITCH_ATTR_EXT_RESTART_ISSU;
 }
 
+std::optional<sai_attr_id_t>
+SaiSwitchTraits::Attributes::AttributeDelayDropCongThreshold::operator()() {
+  return std::nullopt;
+}
+
 std::optional<sai_attr_id_t> SaiSwitchTraits::Attributes::
     AttributeForceTrafficOverFabricWrapper::operator()() {
   return SAI_SWITCH_ATTR_FORCE_TRAFFIC_OVER_FABRIC;

fboss/agent/hw/sai/api/oss/SwitchApi.cpp

@@ -38,6 +38,11 @@ SaiSwitchTraits::Attributes::AttributeRestartIssuWrapper::operator()() {
   return std::nullopt;
 }
 
+std::optional<sai_attr_id_t>
+SaiSwitchTraits::Attributes::AttributeDelayDropCongThreshold::operator()() {
+  return std::nullopt;
+}
+
 std::optional<sai_attr_id_t> SaiSwitchTraits::Attributes::
     AttributeForceTrafficOverFabricWrapper::operator()() {
   return std::nullopt;

fboss/agent/hw/sai/api/tajo/SwitchApi.cpp

@@ -52,6 +52,15 @@ SaiSwitchTraits::Attributes::AttributeRestartIssuWrapper::operator()() {
 #endif
 }
 
+std::optional<sai_attr_id_t>
+SaiSwitchTraits::Attributes::AttributeDelayDropCongThreshold::operator()() {
+#if defined(TAJO_SDK_VERSION_1_42_8)
+  return SAI_SWITCH_ATTR_EXT_DELAY_DROP_CONG_THRESHOLD;
+#else
+  return std::nullopt;
+#endif
+}
+
 std::optional<sai_attr_id_t> SaiSwitchTraits::Attributes::
     AttributeForceTrafficOverFabricWrapper::operator()() {
   return std::nullopt;

fboss/agent/hw/sai/switch/SaiSwitchManager.cpp

@@ -45,6 +45,11 @@ DEFINE_bool(
     false,
     "Flag to indicate whether to skip setting source mac in Sai switch during wb");
 
+DEFINE_uint32(
+    delay_drop_congestion_threshold,
+    0,
+    "Delay drop congestion threshold");
+
 namespace {
 using namespace facebook::fboss;
 sai_hash_algorithm_t toSaiHashAlgo(cfg::HashingAlgorithm algo) {

fboss/agent/hw/sai/tracer/SwitchApiTracer.cpp

@@ -122,6 +122,7 @@ void handleExtensionAttributes() {
   SAI_EXT_ATTR_MAP(Switch, VoqLatencyMinLevel2Ns);
   SAI_EXT_ATTR_MAP(Switch, VoqLatencyMaxLevel2Ns);
   SAI_EXT_ATTR_MAP(Switch, ReachabilityGroupList);
+  SAI_EXT_ATTR_MAP(Switch, DelayDropCongThreshold);
 }
 
 } // namespace

fboss/agent/platforms/sai/SaiPlatform.cpp

@@ -642,6 +642,7 @@ SaiSwitchTraits::CreateAttributes SaiPlatform::getSwitchAttributes(
 #if SAI_API_VERSION >= SAI_VERSION(1, 14, 0)
       std::nullopt, // ARS profile
 #endif
+      std::nullopt, // Delay Drop Cong Threshold
   };
 }