src/bus.py

"""
Bus Module - Data Transfer Logic

This module simulates memory movement and data transfer logic between
different logical components (SSD, RAM, VRAM) with bandwidth simulation.
"""

import asyncio
import time
import numpy as np
from typing import Dict, Any, Optional, Tuple, List
from enum import Enum
from dataclasses import dataclass


class BusType(Enum):
    """Types of data buses in the system."""
    SYSTEM_RAM = "system_ram"
    VRAM_BUS = "vram_bus"
    STORAGE_BUS = "storage_bus"
    PCIE = "pcie"
    MEMORY_CONTROLLER = "memory_controller"


@dataclass
class BusSpecification:
    """Specifications for a data bus."""
    name: str
    bandwidth_gbps: float  # Gigabytes per second
    latency_ms: float      # Milliseconds
    max_concurrent_transfers: int
    bus_width_bits: int


@dataclass
class TransferRequest:
    """Represents a data transfer request."""
    transfer_id: str
    transfer_type: TransferType
    source_address: int
    destination_address: int
    size_bytes: int
    priority: int = 0
    created_time: float = 0.0
    start_time: float = 0.0
    end_time: float = 0.0
    status: str = "pending"  # pending, in_progress, completed, failed


class DataBus:
    """Represents a single data bus with bandwidth and latency simulation."""
    
    def __init__(self, spec: BusSpecification):
        self.spec = spec
        self.active_transfers: List[TransferRequest] = []
        self.completed_transfers: List[TransferRequest] = []
        self.transfer_queue = asyncio.Queue()
        
        # Statistics
        self.total_bytes_transferred = 0
        self.total_transfer_time = 0.0
        self.transfer_count = 0
        
    async def submit_transfer(self, request: TransferRequest) -> str:
        """Submit a transfer request to the bus."""
        request.created_time = time.time()
        await self.transfer_queue.put(request)
        return request.transfer_id
        
    async def process_transfers(self):
        """Process transfer requests with bandwidth and latency simulation."""
        while True:
            try:
                # Wait for a transfer request
                request = await self.transfer_queue.get()
                
                # Check if we can start this transfer (concurrent limit)
                if len(self.active_transfers) >= self.spec.max_concurrent_transfers:
                    # Put it back and wait
                    await self.transfer_queue.put(request)
                    await asyncio.sleep(0.001)  # Small delay
                    continue
                    
                # Start the transfer
                await self._execute_transfer(request)
                
            except asyncio.CancelledError:
                break
            except Exception as e:
                print(f"Error processing transfer on bus {self.spec.name}: {e}")
                
    async def _execute_transfer(self, request: TransferRequest):
        """Execute a single transfer with realistic timing."""
        request.status = "in_progress"
        request.start_time = time.time()
        self.active_transfers.append(request)
        
        try:
            # Calculate transfer time based on bandwidth
            transfer_time_seconds = request.size_bytes / (self.spec.bandwidth_gbps * 1e9)
            
            # Add latency
            total_time = transfer_time_seconds + (self.spec.latency_ms / 1000.0)
            
            # Simulate the transfer delay
            await asyncio.sleep(total_time)
            
            # Complete the transfer
            request.status = "completed"
            request.end_time = time.time()
            
            # Update statistics
            self.total_bytes_transferred += request.size_bytes
            self.total_transfer_time += total_time
            self.transfer_count += 1
            
            print(f"Transfer {request.transfer_id} completed: "
                  f"{request.size_bytes:,} bytes in {total_time:.4f}s "
                  f"({request.size_bytes / (1024**2) / total_time:.2f} MB/s)")
            
        except Exception as e:
            request.status = "failed"
            print(f"Transfer {request.transfer_id} failed: {e}")
            
        finally:
            # Remove from active transfers
            if request in self.active_transfers:
                self.active_transfers.remove(request)
            self.completed_transfers.append(request)
            
    def get_utilization(self) -> float:
        """Get current bus utilization (0.0 to 1.0)."""
        return len(self.active_transfers) / max(1, self.spec.max_concurrent_transfers)
        
    def get_stats(self) -> Dict[str, Any]:
        """Get bus statistics."""
        avg_transfer_time = self.total_transfer_time / max(1, self.transfer_count)
        effective_bandwidth = (self.total_bytes_transferred / (1024**3)) / max(0.001, self.total_transfer_time)
        
        return {
            "bus_name": self.spec.name,
            "bandwidth_gbps": self.spec.bandwidth_gbps,
            "latency_ms": self.spec.latency_ms,
            "total_transfers": self.transfer_count,
            "total_bytes_transferred": self.total_bytes_transferred,
            "total_transfer_time": self.total_transfer_time,
            "avg_transfer_time": avg_transfer_time,
            "effective_bandwidth_gbps": effective_bandwidth,
            "current_utilization": self.get_utilization(),
            "active_transfers": len(self.active_transfers),
            "queued_transfers": self.transfer_queue.qsize()
        }


class BusManager:
    """Manages multiple data buses and coordinates transfers between components."""
    
    def __init__(self):
        self.buses: Dict[str, DataBus] = {}
        self.transfer_counter = 0
        self.running = False
        
        # Initialize standard buses
        self._initialize_standard_buses()
        
    def _initialize_standard_buses(self):
        """Initialize standard system buses with realistic specifications."""
        
        # GDDR7 VRAM Bus (500GB capacity, high bandwidth)
        gddr7_spec = BusSpecification(
            name="GDDR7_VRAM",
            bandwidth_gbps=128.0,  # 128 GB/s (realistic for GDDR7)
            latency_ms=0.1,        # Very low latency
            max_concurrent_transfers=16,
            bus_width_bits=512
        )
        self.add_bus("vram", gddr7_spec)
        
        # PCIe 5.0 Bus (for GPU-CPU communication)
        pcie_spec = BusSpecification(
            name="PCIe_5.0_x16",
            bandwidth_gbps=64.0,   # 64 GB/s for PCIe 5.0 x16
            latency_ms=0.5,        # Higher latency than VRAM
            max_concurrent_transfers=8,
            bus_width_bits=256
        )
        self.add_bus("pcie", pcie_spec)
        
        # System RAM Bus (DDR5)
        ddr5_spec = BusSpecification(
            name="DDR5_System_RAM",
            bandwidth_gbps=51.2,   # 51.2 GB/s for DDR5-6400
            latency_ms=0.2,
            max_concurrent_transfers=4,
            bus_width_bits=128
        )
        self.add_bus("system_ram", ddr5_spec)
        
        # NVMe SSD Bus
        nvme_spec = BusSpecification(
            name="NVMe_SSD",
            bandwidth_gbps=7.0,    # 7 GB/s for high-end NVMe
            latency_ms=0.1,
            max_concurrent_transfers=32,
            bus_width_bits=64
        )
        self.add_bus("storage", nvme_spec)
        
    def add_bus(self, bus_id: str, spec: BusSpecification):
        """Add a new bus to the system."""
        self.buses[bus_id] = DataBus(spec)
        
    async def start(self):
        """Start all bus processing tasks."""
        if self.running:
            return
            
        self.running = True
        
        # Start processing tasks for all buses
        self.bus_tasks = []
        for bus in self.buses.values():
            task = asyncio.create_task(bus.process_transfers())
            self.bus_tasks.append(task)
            
        print(f"Bus manager started with {len(self.buses)} buses")
        
    async def stop(self):
        """Stop all bus processing tasks."""
        if not self.running:
            return
            
        self.running = False
        
        # Cancel all bus tasks
        for task in self.bus_tasks:
            task.cancel()
            
        await asyncio.gather(*self.bus_tasks, return_exceptions=True)
        print("Bus manager stopped")
        
    async def transfer_data(self, bus_id: str, transfer_type: TransferType,
                           source_address: int, destination_address: int,
                           size_bytes: int, priority: int = 0) -> str:
        """Initiate a data transfer on the specified bus."""
        if bus_id not in self.buses:
            raise ValueError(f"Bus {bus_id} not found")
            
        transfer_id = f"transfer_{self.transfer_counter}"
        self.transfer_counter += 1
        
        request = TransferRequest(
            transfer_id=transfer_id,
            transfer_type=transfer_type,
            source_address=source_address,
            destination_address=destination_address,
            size_bytes=size_bytes,
            priority=priority
        )
        
        bus = self.buses[bus_id]
        await bus.submit_transfer(request)
        
        return transfer_id
        
    async def copy_to_vram(self, source_address: int, vram_address: int, 
                          size_bytes: int) -> str:
        """Copy data from system memory to VRAM."""
        return await self.transfer_data(
            "vram", TransferType.WRITE, source_address, vram_address, size_bytes
        )
        
    async def copy_from_vram(self, vram_address: int, destination_address: int,
                            size_bytes: int) -> str:
        """Copy data from VRAM to system memory."""
        return await self.transfer_data(
            "vram", TransferType.READ, vram_address, destination_address, size_bytes
        )
        
    async def load_from_storage(self, storage_address: int, ram_address: int,
                               size_bytes: int) -> str:
        """Load data from storage to system RAM."""
        return await self.transfer_data(
            "storage", TransferType.READ, storage_address, ram_address, size_bytes
        )
        
    async def save_to_storage(self, ram_address: int, storage_address: int,
                             size_bytes: int) -> str:
        """Save data from system RAM to storage."""
        return await self.transfer_data(
            "storage", TransferType.WRITE, ram_address, storage_address, size_bytes
        )
        
    def get_bus_stats(self, bus_id: str) -> Optional[Dict[str, Any]]:
        """Get statistics for a specific bus."""
        if bus_id in self.buses:
            return self.buses[bus_id].get_stats()
        return None
        
    def get_all_stats(self) -> Dict[str, Any]:
        """Get statistics for all buses."""
        stats = {
            "total_buses": len(self.buses),
            "running": self.running,
            "buses": {}
        }
        
        total_bandwidth = 0
        total_utilization = 0
        
        for bus_id, bus in self.buses.items():
            bus_stats = bus.get_stats()
            stats["buses"][bus_id] = bus_stats
            total_bandwidth += bus_stats["bandwidth_gbps"]
            total_utilization += bus_stats["current_utilization"]
            
        stats["total_bandwidth_gbps"] = total_bandwidth
        stats["avg_utilization"] = total_utilization / len(self.buses) if self.buses else 0
        
        return stats
        
    async def benchmark_bus(self, bus_id: str, test_size_mb: int = 100) -> Dict[str, Any]:
        """Benchmark a specific bus with test transfers."""
        if bus_id not in self.buses:
            raise ValueError(f"Bus {bus_id} not found")
            
        print(f"Benchmarking bus {bus_id} with {test_size_mb} MB transfers...")
        
        test_size_bytes = test_size_mb * 1024 * 1024
        num_tests = 10
        
        start_time = time.time()
        transfer_ids = []
        
        # Submit multiple test transfers
        for i in range(num_tests):
            transfer_id = await self.transfer_data(
                bus_id, TransferType.COPY, 
                i * test_size_bytes, (i + 1000) * test_size_bytes, 
                test_size_bytes
            )
            transfer_ids.append(transfer_id)
            
        # Wait for all transfers to complete
        bus = self.buses[bus_id]
        while len(bus.active_transfers) > 0 or bus.transfer_queue.qsize() > 0:
            await asyncio.sleep(0.1)
            
        end_time = time.time()
        total_time = end_time - start_time
        total_data_gb = (test_size_bytes * num_tests) / (1024**3)
        effective_bandwidth = total_data_gb / total_time
        
        return {
            "bus_id": bus_id,
            "test_size_mb": test_size_mb,
            "num_transfers": num_tests,
            "total_time_seconds": total_time,
            "total_data_gb": total_data_gb,
            "effective_bandwidth_gbps": effective_bandwidth,
            "theoretical_bandwidth_gbps": bus.spec.bandwidth_gbps,
            "efficiency_percent": (effective_bandwidth / bus.spec.bandwidth_gbps) * 100
        }


if __name__ == "__main__":
    # Test the bus system
    async def test_bus_system():
        print("Testing Bus System...")
        
        # Create bus manager
        bus_manager = BusManager()
        await bus_manager.start()
        
        # Test individual transfers
        print("\nTesting individual transfers...")
        
        # Test VRAM transfer (large texture upload)
        texture_size = 64 * 1024 * 1024  # 64 MB texture
        vram_transfer = await bus_manager.copy_to_vram(0x1000, 0x10000000, texture_size)
        print(f"Submitted VRAM transfer: {vram_transfer}")
        
        # Test storage transfer (loading assets)
        asset_size = 128 * 1024 * 1024  # 128 MB asset
        storage_transfer = await bus_manager.load_from_storage(0x0, 0x2000, asset_size)
        print(f"Submitted storage transfer: {storage_transfer}")
        
        # Test PCIe transfer (CPU-GPU communication)
        command_size = 4 * 1024  # 4 KB command buffer
        pcie_transfer = await bus_manager.transfer_data(
            "pcie", TransferType.WRITE, 0x3000, 0x20000000, command_size
        )
        print(f"Submitted PCIe transfer: {pcie_transfer}")
        
        # Wait for transfers to complete
        print("\nWaiting for transfers to complete...")
        await asyncio.sleep(2.0)
        
        # Print statistics
        print("\nBus Statistics:")
        all_stats = bus_manager.get_all_stats()
        for bus_id, bus_stats in all_stats["buses"].items():
            print(f"\n{bus_id}:")
            print(f"  Bandwidth: {bus_stats["bandwidth_gbps"]:.1f} GB/s")
            print(f"  Transfers: {bus_stats["total_transfers"]}")
            print(f"  Data transferred: {bus_stats["total_bytes_transferred"] / (1024**2):.1f} MB")
            print(f"  Effective bandwidth: {bus_stats["effective_bandwidth_gbps"]:.2f} GB/s")
            print(f"  Utilization: {bus_stats["current_utilization"]:.1%}")
            
        # Benchmark each bus
        print("\nBenchmarking buses...")
        for bus_id in ["vram", "pcie", "system_ram", "storage"]:
            try:
                benchmark_result = await bus_manager.benchmark_bus(bus_id, test_size_mb=50)
                print(f"\n{bus_id} benchmark:")
                print(f"  Effective bandwidth: {benchmark_result["effective_bandwidth_gbps"]:.2f} GB/s")
                print(f"  Theoretical bandwidth: {benchmark_result["theoretical_bandwidth_gbps"]:.2f} GB/s")
                print(f"  Efficiency: {benchmark_result["efficiency_percent"]:.1f}%")
            except Exception as e:
                print(f"Benchmark failed for {bus_id}: {e}")
                
        # Stop bus manager
        await bus_manager.stop()
        print("\nBus system test completed!")
        
    # Run the test
    asyncio.run(test_bus_system())