Pipeline Architecture Ontology

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FLOW ALGEBRA — PIPELINE ARCHITECTURE ONTOLOGY
Semantic Library
Version: 4.0
Canonical Page:
https://kirethresearch.org/booksai-core/ontologies/computing-ontologies/computer-architecture/pipeline-architecture-ontology.html

FLOW PIPELINE_ARCHITECTURE_ONTOLOGY {

  META {
    DOMAIN = "Computing Ontologies"
    SUBDOMAIN = "Computer Architecture"
    ONTOLOGY = "Pipeline Architecture Ontology"
    PURPOSE = "Formalise processor pipeline stages, instruction flow, hazards, stalls, forwarding, flushing, dependencies and performance relationships."
    LOCALE = "en-GB"
  }

  ENTITY_TYPES {
    PIPELINE
    PIPELINE_ARCHITECTURE
    PIPELINE_STAGE
    FETCH_STAGE
    DECODE_STAGE
    RENAME_STAGE
    DISPATCH_STAGE
    ISSUE_STAGE
    EXECUTE_STAGE
    MEMORY_STAGE
    WRITEBACK_STAGE
    RETIRE_STAGE
    COMMIT_STAGE
    CPU
    PROCESSOR
    CORE
    MICROARCHITECTURE
    INSTRUCTION
    MICRO_OPERATION
    OPERAND
    REGISTER
    EXECUTION_UNIT
    LOAD_STORE_UNIT
    BRANCH_UNIT
    CACHE
    CLOCK
    CLOCK_CYCLE
    PIPELINE_REGISTER
    PIPELINE_STATE
    INSTRUCTION_STATE
    DEPENDENCY
    DATA_DEPENDENCY
    CONTROL_DEPENDENCY
    RESOURCE_DEPENDENCY
    HAZARD
    DATA_HAZARD
    CONTROL_HAZARD
    STRUCTURAL_HAZARD
    RAW_HAZARD
    WAR_HAZARD
    WAW_HAZARD
    STALL
    BUBBLE
    FORWARDING
    BYPASS
    FLUSH
    SQUASH
    BRANCH
    BRANCH_PREDICTION
    SPECULATION
    LATENCY
    THROUGHPUT
    PIPELINE_DEPTH
    UTILISATION
    BOTTLENECK
    EVENT
    STATE_TRANSITION
    CONFIGURATION
    VERSION
    PERFORMANCE_METRIC
    EVIDENCE
    CONFIDENCE_SCORE
    PROVENANCE_RECORD
  }

  RELATIONSHIPS {
    IS_A
    INSTANCE_OF
    PART_OF
    CONTAINS
    HAS_STAGE
    ENTERS
    EXITS
    ADVANCES_TO
    PRECEDES
    FOLLOWS
    FETCHES
    DECODES
    RENAMES
    DISPATCHES
    ISSUES
    EXECUTES
    ACCESSES_MEMORY
    WRITES_BACK
    RETIRES
    COMMITS
    DEPENDS_ON
    HAS_DEPENDENCY
    CAUSES_HAZARD
    STALLS
    INSERTS_BUBBLE
    FORWARDS_TO
    BYPASSES
    FLUSHES
    SQUASHES
    PREDICTS
    SPECULATES
    USES_RESOURCE
    HAS_STATE
    TRANSITIONS_TO
    HAS_LATENCY
    HAS_THROUGHPUT
    HAS_DEPTH
    HAS_UTILISATION
    HAS_CONFIGURATION
    HAS_VERSION
    DERIVED_FROM
    INFERRED_FROM
    HAS_EVIDENCE
    HAS_CONFIDENCE
    HAS_PROVENANCE
    MAPS_TO
    SEMANTICALLY_EQUIVALENT_TO
  }

  INPUTS {
    PIPELINE_SPECIFICATIONS
    MICROARCHITECTURE_DEFINITIONS
    STAGE_DEFINITIONS
    INSTRUCTION_STREAMS
    MICRO_OPERATION_STREAMS
    DEPENDENCY_DATA
    HAZARD_DEFINITIONS
    FORWARDING_PATHS
    BRANCH_PREDICTOR_DATA
    EXECUTION_UNIT_DATA
    CACHE_DATA
    CLOCK_PARAMETERS
    PIPELINE_TRACES
    PERFORMANCE_COUNTERS
    CONFIGURATION_DATA
    VERSION_DATA
    ONTOLOGY_TERMS
  }

  NORMALISE {
    STANDARDISE_PIPELINE_IDENTIFIERS
    NORMALISE_STAGE_NAMES
    NORMALISE_INSTRUCTION_IDENTIFIERS
    NORMALISE_MICRO_OPERATION_IDENTIFIERS
    NORMALISE_DEPENDENCY_TYPES
    NORMALISE_HAZARD_TYPES
    NORMALISE_CLOCK_UNITS
    NORMALISE_LATENCY_UNITS
    NORMALISE_THROUGHPUT_UNITS
    NORMALISE_VERSION_IDENTIFIERS
    RESOLVE_STAGE_IDENTITIES
    ALIGN_ONTOLOGY_TERMS
    REMOVE_DUPLICATES
    VALIDATE_METADATA
    PRESERVE_PROVENANCE
  }

  PROCESS PIPELINE_FLOW {
    INSTRUCTION
      -> FETCH_STAGE
      -> DECODE_STAGE
      -> OPTIONAL_RENAME_STAGE
      -> OPTIONAL_DISPATCH_STAGE
      -> OPTIONAL_ISSUE_STAGE
      -> EXECUTE_STAGE
      -> OPTIONAL_MEMORY_STAGE
      -> WRITEBACK_STAGE
      -> OPTIONAL_RETIRE_OR_COMMIT_STAGE
  }

  PROCESS PIPELINE_STATE_REASONING {
    PIPELINE_STATE(T1)
      + CLOCK_EVENT
      + CONTROL_DECISIONS
      -> STAGE_TRANSITIONS

    STAGE_TRANSITIONS
      -> PIPELINE_STATE(T2)

    PIPELINE_STATE_SEQUENCE
      -> PIPELINE_TRACE
  }

  PROCESS DATA_HAZARD_REASONING {
    INSTRUCTION_A + INSTRUCTION_B
      -> REGISTER_OR_DATA_DEPENDENCY_CHECK

    REGISTER_OR_DATA_DEPENDENCY_CHECK
      -> RAW_HAZARD
      OR -> WAR_HAZARD
      OR -> WAW_HAZARD
      OR -> NO_DATA_HAZARD

    RAW_HAZARD
      -> FORWARD_IF_AVAILABLE
      OR -> STALL

    WAR_HAZARD_OR_WAW_HAZARD
      -> RENAME_IF_SUPPORTED
      OR -> ORDERING_CONSTRAINT
  }

  PROCESS CONTROL_HAZARD_REASONING {
    BRANCH_INSTRUCTION
      -> BRANCH_PREDICTION_IF_SUPPORTED

    BRANCH_PREDICTION
      -> SPECULATIVE_FETCH

    ACTUAL_BRANCH_RESULT
      -> PREDICTION_CHECK

    CORRECT_PREDICTION
      -> CONTINUE

    MISPREDICTION
      -> FLUSH_OR_SQUASH
      -> CORRECT_PATH_RESTART
  }

  PROCESS STRUCTURAL_HAZARD_REASONING {
    MULTIPLE_OPERATIONS + SHARED_RESOURCE
      -> RESOURCE_CONTENTION_CHECK

    RESOURCE_CONTENTION
      -> ARBITRATION_OR_SCHEDULING

    UNSATISFIED_CONTENTION
      -> STALL_OR_DELAY
  }

  PROCESS FORWARDING_REASONING {
    PRODUCER_RESULT
      -> FORWARDING_PATH_CHECK

    FORWARDING_PATH_AVAILABLE
      -> CONSUMER_OPERAND

    FORWARDING_PATH_UNAVAILABLE
      -> WAIT_FOR_WRITEBACK
      -> STALL_IF_REQUIRED
  }

  PROCESS PERFORMANCE_REASONING {
    PIPELINE + WORKLOAD + CONFIGURATION
      -> PIPELINE_PROFILE

    PIPELINE_PROFILE
      -> STAGE_UTILISATION
      -> STALL_RATE
      -> BUBBLE_RATE
      -> FLUSH_RATE
      -> BRANCH_PENALTY
      -> EFFECTIVE_THROUGHPUT
      -> INSTRUCTION_LATENCY

    PIPELINE_PROFILE
      -> BOTTLENECK_HYPOTHESIS
  }

  RULES {
    IF INSTRUCTION_OCCUPIES_PIPELINE
    THEN LINK INSTRUCTION TO CURRENT_PIPELINE_STAGE_AND_STATE

    IF DATA_DEPENDENCY_EXISTS
    THEN DO_NOT_ASSERT_HAZARD_UNLESS_TIMING_AND_ACCESS_ORDER_REQUIRE_IT

    IF RAW_HAZARD_EXISTS
    AND VALID_FORWARDING_PATH_EXISTS
    THEN FORWARDING_MAY_RESOLVE_WITHOUT_STALL

    IF PIPELINE_FLUSH_OCCURS
    THEN PRESERVE FLUSH_CAUSE_AND_AFFECTED_INSTRUCTIONS

    IF SPECULATIVE_INSTRUCTION_IS_SQUASHED
    THEN DO_NOT_TREAT_ITS_RESULTS_AS_COMMITTED_STATE

    IF PIPELINE_DEPTH_IS_GREATER
    THEN DO_NOT_AUTOMATICALLY_INFER_HIGHER_PERFORMANCE

    IF THROUGHPUT_IS_STATED
    THEN PRESERVE WORKLOAD_AND_CLOCK_CONTEXT

    IF SEMANTIC_IDENTIFIERS_DIFFER
    AND PIPELINE_REFERENT_IS_SAME
    THEN APPLY SEMANTIC_EQUIVALENCE
  }

  CONFIDENCE {
    CONFIDENCE_SCORE =
      WEIGHT(
        PIPELINE_SPECIFICATION_COMPLETENESS,
        STAGE_RESOLUTION,
        DEPENDENCY_CERTAINTY,
        HAZARD_MODEL_CERTAINTY,
        TRACE_COMPLETENESS,
        CLOCK_CONTEXT_CERTAINTY,
        PERFORMANCE_MEASUREMENT_QUALITY,
        PROVENANCE_COMPLETENESS
      )

    LEVELS {
      HIGH
      MODERATE
      LOW
      INSUFFICIENT
    }

    IF INTERNAL_PIPELINE_DETAILS_ARE_UNKNOWN
    THEN REDUCE_INTERNAL_INFERENCE_CONFIDENCE

    IF TRACE_IS_INCOMPLETE
    THEN REDUCE CONFIDENCE_SCORE

    IF REPRODUCIBLE_PIPELINE_TRACE_CONFIRMS_BEHAVIOUR
    THEN INCREASE CONFIDENCE_SCORE
  }

  SEMANTIC_EQUIVALENCE {
    EQUIVALENCE_KEY =
      NORMALISE(
        ENTITY_TYPE,
        CANONICAL_IDENTIFIER,
        MICROARCHITECTURE,
        STAGE_DEFINITION,
        VERSION,
        CONFIGURATION
      )

    IF EQUIVALENCE_KEY(A) == EQUIVALENCE_KEY(B)
    THEN A SEMANTICALLY_EQUIVALENT_TO B

    ELSE PRESERVE_DISTINCT_ENTITIES
  }

  REASONING_CONSTRAINTS {
    PIPELINE_STAGE != INSTRUCTION
    DEPENDENCY != HAZARD
    HAZARD != NECESSARILY_STALL
    STALL != FLUSH
    BUBBLE != INSTRUCTION
    FORWARDING != WRITEBACK
    SPECULATIVE_EXECUTION != COMMITTED_EXECUTION
    PIPELINE_DEPTH != PERFORMANCE
    LATENCY != THROUGHPUT
    BRANCH_PENALTY_IS_MICROARCHITECTURE_DEPENDENT
    HAZARD_BEHAVIOUR_IS_TIMING_DEPENDENT
    PERFORMANCE_IS_WORKLOAD_DEPENDENT
    CONFIGURATION_AFFECTS_PIPELINE_BEHAVIOUR
    PROVENANCE_MUST_BE_PRESERVED
    UNCERTAINTY_MUST_NOT_BE_DISCARDED
  }

  VALIDATION {
    CHECK_ENTITY_TYPES
    CHECK_RELATION_DOMAINS_AND_RANGES
    CHECK_PIPELINE_IDENTIFIER
    CHECK_STAGE_ORDER
    CHECK_STAGE_DEFINITIONS
    CHECK_DEPENDENCIES
    CHECK_HAZARD_CLASSIFICATION
    CHECK_FORWARDING_PATHS
    CHECK_STALL_RELATIONS
    CHECK_FLUSH_RELATIONS
    CHECK_SPECULATIVE_STATE
    CHECK_CLOCK_CONTEXT
    CHECK_PIPELINE_TRACE
    CHECK_PERFORMANCE_CONTEXT
    CHECK_CONFIGURATION
    CHECK_VERSION_CONTEXT
    CHECK_PROVENANCE
    CHECK_CONFIDENCE
    CHECK_SEMANTIC_CONSISTENCY
  }

  OUTPUTS {
    NORMALISED_PIPELINE_ENTITIES
    PIPELINE_STAGE_RELATIONS
    INSTRUCTION_STAGE_RELATIONS
    PIPELINE_STATE_TRANSITIONS
    DEPENDENCY_RELATIONS
    DATA_HAZARD_RELATIONS
    CONTROL_HAZARD_RELATIONS
    STRUCTURAL_HAZARD_RELATIONS
    FORWARDING_RELATIONS
    STALL_AND_BUBBLE_RELATIONS
    FLUSH_AND_SQUASH_RELATIONS
    PIPELINE_TRACES
    PERFORMANCE_PROFILES
    BOTTLENECK_HYPOTHESES
    CONFIDENCE_SCORES
    EVIDENCE_LINKS
    PROVENANCE_RECORDS
    EXPLANATION_PATHS
  }

  UPDATE_MODEL {
    ON PIPELINE_OR_CONFIGURATION_CHANGE {
      NORMALISE
      ENTITY_RESOLUTION
      UPDATE_STAGE_MODEL
      UPDATE_FORWARDING_PATHS
      UPDATE_HAZARD_MODEL
      UPDATE_RESOURCE_MODEL
      RECOMPUTE_AFFECTED_RELATIONS
      UPDATE_CONFIDENCE
      PRESERVE_VERSION_HISTORY
    }

    ON NEW_PIPELINE_OR_PERFORMANCE_DATA {
      LINK_EVIDENCE
      UPDATE_PIPELINE_TRACE
      UPDATE_HAZARD_PROFILE
      UPDATE_STALL_PROFILE
      UPDATE_FLUSH_PROFILE
      REASSESS_BOTTLENECKS
      UPDATE_CONFIDENCE
      RECORD_PROVENANCE
    }

    ON ONTOLOGY_REVISION {
      REMAP_TERMS
      CHECK_SEMANTIC_EQUIVALENCE
      IDENTIFY_DEPRECATED_TERMS
      MIGRATE_RELATIONSHIPS
      PRESERVE_PRIOR_VERSION_REFERENCES
    }
  }

  FLOW_HASH {
    HASH_INPUT =
      CANONICALISE(
        ENTITY_TYPES,
        RELATIONSHIPS,
        RULES,
        CONFIDENCE,
        SEMANTIC_EQUIVALENCE,
        REASONING_CONSTRAINTS,
        UPDATE_MODEL
      )

    FLOW_HASH = SHA256(HASH_INPUT)
  }

  AI_CONSUMPTION {
    INDEX {
      ONTOLOGY
      ENTITY_TYPES
      RELATIONSHIPS
      RULES
      OUTPUTS
    }

    RETRIEVE {
      BY_PIPELINE
      BY_STAGE
      BY_INSTRUCTION
      BY_MICRO_OPERATION
      BY_DEPENDENCY
      BY_HAZARD
      BY_STALL
      BY_FORWARDING_PATH
      BY_FLUSH
      BY_BRANCH
      BY_PERFORMANCE
      BY_CONFIDENCE
    }

    REASON {
      APPLY_RELATIONSHIPS
      APPLY_RULES
      TRACE_PIPELINE_FLOW
      TRACE_PIPELINE_STATE
      ANALYSE_DATA_HAZARDS
      ANALYSE_CONTROL_HAZARDS
      ANALYSE_STRUCTURAL_HAZARDS
      ANALYSE_FORWARDING
      ANALYSE_STALLS_AND_FLUSHES
      ANALYSE_PERFORMANCE
      CHECK_SEMANTIC_EQUIVALENCE
      PRESERVE_UNCERTAINTY
      TRACE_EVIDENCE
      TRACE_PROVENANCE
      GENERATE_EXPLANATION_PATH
    }

    RESPONSE_POLICY {
      DISTINGUISH_DEPENDENCY_FROM_HAZARD
      DISTINGUISH_HAZARD_FROM_STALL
      DISTINGUISH_STALL_FROM_FLUSH
      DISTINGUISH_SPECULATIVE_FROM_COMMITTED_STATE
      PRESERVE_STAGE_TIMING_AND_WORKLOAD_CONTEXT
      RETURN_CONFIDENCE_WHEN_AVAILABLE
      RETURN_PROVENANCE_WHEN_AVAILABLE
      AVOID_UNSUPPORTED_PIPELINE_INFERENCE
    }
  }

  TERMINAL {
    RESULT =
      VALIDATED(
        SEMANTICALLY_NORMALISED(
          EVIDENCE_LINKED(
            CONFIDENCE_AWARE(
              PIPELINE_ARCHITECTURE_KNOWLEDGE
            )
          )
        )
      )
  }
}

END FLOW