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Chapter 10: Real-World Examples

Example 1: Hello Actor

const std = @import("std");
const zbmd = @import("zbmd");

pub fn main() !void {
    // Initialize actor system
    var system = try zbmd.ActorSystem.init(.{
        .workers = 4,
    });
    defer system.deinit();

    // Create an echo actor
    const echo = try system.spawn(echoActor, .{});

    // Send message
    try echo.send(.{ .text = "Hello, Actor!" });

    // Receive reply
    const reply = try echo.call(.{ .get_reply = {} }, 1000);
    std.debug.print("Reply: {s}\n", .{reply.text});
}

fn echoActor(self: *zbmd.Actor, msg: zbmd.Message) !void {
    switch (msg.payload) {
        .text => |t| {
            std.debug.print("Echo actor received: {s}\n", .{t});
            self.last_message = t;
        },
        .get_reply => {
            try msg.reply(.{ .text = self.last_message });
        },
        else => {},
    }
}

Example 2: Supervised Counter

const std = @import("std");
const zbmd = @import("zbmd");

pub fn main() !void {
    var system = try zbmd.ActorSystem.init(.{});
    defer system.deinit();

    // Create supervisor
    const supervisor = try system.spawn(zbmd.Supervisor, .{
        .strategy = .one_for_one,
        .max_restarts = 10,
    });

    // Start supervised counter
    const counter = try supervisor.startChild(counterActor, .{
        .restart = .permanent,
    });

    // Increment counter
    for (0..100) |i| {
        // Randomly crash to test supervision
        if (i % 20 == 19) {
            try counter.send(.{ .crash = {} });
        } else {
            try counter.send(.{ .increment = 1 });
        }
    }

    // Get final value
    const value = try counter.call(.{ .get_value = {} }, 1000);
    std.debug.print("Final counter value: {}\n", .{value});
}

fn counterActor(self: *zbmd.Actor, msg: zbmd.Message) !void {
    const state = @ptrCast(*CounterState, self.state);

    switch (msg.payload) {
        .increment => |n| {
            state.value += n;
        },
        .get_value => {
            try msg.reply(.{ .value = state.value });
        },
        .crash => {
            return error.IntentionalCrash;
        },
        else => {},
    }
}

const CounterState = struct {
    value: i32 = 0,
};

Example 3: GPU Vector Addition

const std = @import("std");
const zbmd = @import("zbmd");

pub fn main() !void {
    var system = try zbmd.ActorSystem.init(.{
        .gpu_backends = .{ .cuda, .rocm, .vulkan },
    });
    defer system.deinit();

    // Detect best GPU
    const gpu = try zbmd.selectBestGpu();
    std.debug.print("Using GPU: {s}\n", .{gpu.name});

    // Create tensor actors
    const n = 1_000_000;
    const a = try system.spawn(zbmd.TensorActor, .{
        .shape = .{n},
        .device = gpu,
        .init_value = .ones,
    });

    const b = try system.spawn(zbmd.TensorActor, .{
        .shape = .{n},
        .device = gpu,
        .init_value = .range,
    });

    // Perform addition
    const c = try a.call(.{
        .add = .{ .other = b }
    }, 1000);

    // Verify result
    const first_elements = try c.call(.{
        .get_slice = .{ .start = 0, .end = 10 }
    }, 1000);

    std.debug.print("Result: ", .{});
    for (first_elements) |val| {
        std.debug.print("{d:.2} ", .{val});
    }
    std.debug.print("\n", .{});
}

Example 4: Simple Neural Network Training

const std = @import("std");
const zbmd = @import("zbmd");

pub fn main() !void {
    var system = try zbmd.ActorSystem.init(.{
        .gpu_backends = .{ .cuda, .rocm },
    });
    defer system.deinit();

    // Create model
    const model = try system.spawn(zbmd.ModelActor, .{
        .architecture = &[_]zbmd.LayerSpec{
            .{ .type = .dense, .units = 784, .activation = .none },
            .{ .type = .dense, .units = 128, .activation = .relu },
            .{ .type = .dense, .units = 10, .activation = .softmax },
        },
    });

    // Create optimizer
    const optimizer = try system.spawn(zbmd.OptimizerActor, .{
        .type = .adam,
        .learning_rate = 0.001,
    });

    // Create training supervisor
    const trainer = try system.spawn(zbmd.TrainingSupervisor, .{
        .model = model,
        .optimizer = optimizer,
        .strategy = .one_for_all,  // Restart all on failure
    });

    // Load dataset
    const dataset = try zbmd.Dataset.load("mnist.tfrecord");

    // Training loop with fault tolerance
    const result = try trainer.call(.{
        .train = .{
            .dataset = dataset,
            .epochs = 10,
            .batch_size = 32,
            .checkpoint_interval = 100,
        }
    }, 600_000);  // 10 minute timeout

    std.debug.print("Training completed!\n", .{});
    std.debug.print("Final accuracy: {d:.2}%\n", .{result.accuracy * 100});
    std.debug.print("Training time: {d:.2}s\n", .{result.elapsed_seconds});
    std.debug.print("GPU failures recovered: {}\n", .{result.recovery_count});
}

Example 5: Distributed Training

const std = @import("std");
const zbmd = @import("zbmd");

pub fn main() !void {
    // Parse command line args
    const args = try std.process.argsAlloc(std.heap.page_allocator);
    defer std.process.argsFree(std.heap.page_allocator, args);

    const node_id = try std.fmt.parseInt(u32, args[1], 10);
    const num_nodes = try std.fmt.parseInt(u32, args[2], 10);

    // Initialize distributed actor system
    var system = try zbmd.DistributedSystem.init(.{
        .node_id = node_id,
        .cluster_size = num_nodes,
        .seeds = &[_][]const u8{
            "node0:9000",
            "node1:9000",
        },
    });
    defer system.deinit();

    // Wait for cluster formation
    try system.waitForCluster();
    std.debug.print("Node {} joined cluster\n", .{node_id});

    // Create distributed model
    const model = if (node_id == 0) blk: {
        // Master node creates model
        break :blk try system.spawn(zbmd.DistributedModel, .{
            .architecture = transformer_config,
            .distribution = .{
                .strategy = .data_parallel,
                .nodes = num_nodes,
            },
        });
    } else blk: {
        // Worker nodes wait for model
        break :blk try system.lookupActor("distributed_model");
    };

    // Distributed training
    if (node_id == 0) {
        // Master coordinates training
        const result = try model.call(.{
            .train_distributed = .{
                .dataset = "imagenet",
                .epochs = 100,
                .global_batch_size = 4096,
            }
        }, null);  // No timeout

        std.debug.print("Distributed training complete!\n", .{});
        std.debug.print("Total throughput: {} images/sec\n", .{result.throughput});
    } else {
        // Workers process tasks
        while (true) {
            const task = try system.receiveTask();
            switch (task) {
                .forward => |batch| {
                    const output = try model.forward(batch);
                    try system.sendResult(output);
                },
                .backward => |grad| {
                    try model.backward(grad);
                },
                .terminate => break,
            }
        }
    }
}

const transformer_config = zbmd.ModelConfig{
    .layers = &[_]zbmd.LayerSpec{
        .{ .type = .embedding, .vocab_size = 50000, .dim = 768 },
        .{ .type = .transformer_block, .heads = 12, .dim = 768 },
        // ... more layers
    },
    .parameters = 175_000_000_000,  // 175B parameters
};

Example 6: Production Inference Server

const std = @import("std");
const zbmd = @import("zbmd");

pub fn main() !void {
    var system = try zbmd.ActorSystem.init(.{
        .workers = 32,
        .gpu_backends = .{ .cuda, .rocm },
    });
    defer system.deinit();

    // Load model with multiple replicas
    const model_replicas = try zbmd.ModelReplicas.init(.{
        .model_path = "model.onnx",
        .num_replicas = 4,
        .device_placement = .automatic,
    });

    // Create inference server
    const server = try system.spawn(zbmd.InferenceServer, .{
        .model = model_replicas,
        .batching = .{
            .dynamic = true,
            .max_batch_size = 128,
            .timeout_ms = 10,
        },
        .monitoring = .{
            .prometheus_port = 9090,
            .health_check_port = 8080,
        },
    });

    // Start HTTP server
    try server.call(.{
        .listen = .{
            .port = 8000,
            .max_connections = 10000,
        }
    }, null);

    std.debug.print("Inference server running on :8000\n", .{});
    std.debug.print("Metrics available on :9090/metrics\n", .{});
    std.debug.print("Health check on :8080/health\n", .{});

    // Handle shutdown gracefully
    const sigterm = try std.os.signal.init(.term);
    defer sigterm.deinit();

    _ = try sigterm.wait();
    std.debug.print("Shutting down gracefully...\n", .{});

    try server.send(.{ .shutdown = .graceful });
    try server.waitForTermination();
}

Example 7: Custom Training Loop with Checkpointing

const std = @import("std");
const zbmd = @import("zbmd");

pub fn customTrainingLoop() !void {
    var system = try zbmd.ActorSystem.init(.{});
    defer system.deinit();

    // Create supervised training components
    const supervisor = try system.spawn(zbmd.Supervisor, .{
        .strategy = .rest_for_one,
    });

    const model = try supervisor.startChild(zbmd.ModelActor, .{
        .spec = gpt_model_spec,
        .restart = .permanent,
    });

    const checkpointer = try supervisor.startChild(zbmd.CheckpointActor, .{
        .path = "checkpoints/",
        .restart = .permanent,
    });

    const metrics = try supervisor.startChild(zbmd.MetricsActor, .{
        .restart = .permanent,
    });

    // Custom training loop
    var step: u32 = 0;
    const dataset = try zbmd.Dataset.stream("training_data/");

    while (try dataset.next()) |batch| {
        defer step += 1;

        // Forward pass with retry on failure
        const output = retry: {
            var attempts: u32 = 0;
            while (attempts < 3) : (attempts += 1) {
                if (model.call(.{
                    .forward = .{ .input = batch.inputs }
                }, 1000)) |out| {
                    break :retry out;
                } else |err| {
                    std.debug.print("Forward pass failed: {}, retrying...\n", .{err});
                    std.time.sleep(1_000_000_000);  // 1 second
                }
            }
            return error.MaxRetriesExceeded;
        };

        // Compute loss
        const loss = try computeLoss(output, batch.targets);

        // Backward pass
        try model.send(.{
            .backward = .{ .loss = loss }
        });

        // Log metrics
        try metrics.send(.{
            .record = .{
                .step = step,
                .loss = loss.value,
                .learning_rate = getCurrentLR(step),
            }
        });

        // Checkpoint periodically
        if (step % 1000 == 0) {
            const checkpoint_future = try checkpointer.callAsync(.{
                .save = .{
                    .model = model,
                    .step = step,
                    .metrics = metrics,
                }
            });

            // Continue training while checkpointing
            // Check result later
            defer checkpoint_future.await(10_000) catch |err| {
                std.debug.print("Checkpoint failed: {}\n", .{err});
            };
        }

        // Gradient accumulation
        if (step % 4 == 0) {
            try model.send(.{ .optimizer_step = {} });
        }
    }
}

Example 8: Fault Injection Testing

const std = @import("std");
const zbmd = @import("zbmd");

test "system handles random failures" {
    var system = try zbmd.ActorSystem.init(.{
        .fault_injection = .{
            .enabled = true,
            .actor_crash_rate = 0.01,
            .message_drop_rate = 0.001,
            .gpu_failure_rate = 0.0001,
        },
    });
    defer system.deinit();

    // Create resilient system
    const root_supervisor = try system.spawn(zbmd.Supervisor, .{
        .strategy = .one_for_all,
        .intensity = 100,
        .period = 60_000_000_000,
    });

    // Spawn worker actors
    var workers: [100]zbmd.ActorId = undefined;
    for (&workers) |*w| {
        w.* = try root_supervisor.startChild(workerActor, .{
            .restart = .permanent,
        });
    }

    // Send many messages
    var success_count: u32 = 0;
    var failure_count: u32 = 0;

    for (0..10000) |i| {
        const worker = workers[i % 100];

        if (worker.send(.{ .work = i })) {
            success_count += 1;
        } else |err| {
            failure_count += 1;
            std.debug.print("Message {} failed: {}\n", .{i, err});
        }
    }

    // System should remain functional despite failures
    try testing.expect(success_count > 9900);  // >99% success rate

    // Verify all workers still alive
    for (workers) |w| {
        const alive = try w.call(.{ .ping = {} }, 100);
        try testing.expect(alive);
    }
}

Running the Examples

# Build all examples
zig build examples

# Run specific example
zig build run-hello-actor
zig build run-gpu-training
zig build run-distributed -- 0 4  # node 0 of 4

# Run with different backends
ZBMD_GPU_BACKEND=rocm zig build run-gpu-training
ZBMD_GPU_BACKEND=vulkan zig build run-inference-server

# Run tests
zig build test

# Run benchmarks
zig build bench

# Run with fault injection
ZBMD_FAULT_INJECTION=true zig build run-training

Performance Results

Running on MSI Titan GT77 hx13v:

  • CPU: 13th Gen Intel Core i9-13980HX (32 cores @ 5.60 GHz)
  • GPU: GeForce RTX 4090 Laptop GPU (2.0 GHz GPU / 9.0 GHz VRAM)
  • OS: Linux 6.17.6-200.fc42.x86_64

Actor System Benchmarks

=== Benchmark: Actor Spawn ===
  Iterations: 100
  Mean:       230 ns (0.23 µs)
  Median:     224 ns (0.22 µs)
  Min:        151 ns (0.15 µs)
  Max:        408 ns (0.41 µs)
  P99:        408 ns (0.41 µs)

=== Benchmark: Message Init ===
  Iterations: 100000
  Mean:       43 ns (0.04 µs)
  Median:     43 ns (0.04 µs)
  Min:        41 ns (0.04 µs)
  Max:        2641 ns (2.64 µs)
  P99:        49 ns (0.05 µs)

Bounded Data Structures

=== Benchmark: BoundedQueue Push ===
  Iterations: 10000
  Mean:       10 ns (0.01 µs)
  Median:     10 ns (0.01 µs)
  Min:        9 ns (0.01 µs)
  Max:        261 ns (0.26 µs)
  P99:        12 ns (0.01 µs)

=== Benchmark: BoundedQueue Pop ===
  Iterations: 10000
  Mean:       10 ns (0.01 µs)
  Median:     11 ns (0.01 µs)
  Min:        9 ns (0.01 µs)
  Max:        14 ns (0.01 µs)
  P99:        12 ns (0.01 µs)

GPU Performance

Vector size: 1024 elements (0 MB)
=== Benchmark: GPU Vector Addition ===
  Iterations: 100
  Mean:       28729 ns (28.73 µs)
  Median:     28070 ns (28.07 µs)
  Min:        22350 ns (22.35 µs)
  Max:        53609 ns (53.61 µs)
  P99:        53609 ns (53.61 µs)
  GFLOPS:     35.64

Vector size: 1048576 elements (4 MB)
=== Benchmark: GPU Vector Addition ===
  Iterations: 100
  Mean:       31616 ns (31.62 µs)
  Median:     32535 ns (32.54 µs)
  Min:        25662 ns (25.66 µs)
  Max:        50217 ns (50.22 µs)
  P99:        50217 ns (50.22 µs)
  GFLOPS:     33165.99

Multi-Core Scaling

=== TRUE Multi-Core Scaling (With Optimizations) ===

Workers:  1 ->    17.02 M ops/sec |   1.6x speedup | 162.1% efficiency |   58 ns/op
Workers:  2 ->    37.40 M ops/sec |   3.6x speedup | 178.1% efficiency |   26 ns/op
Workers:  4 ->    56.50 M ops/sec |   5.4x speedup | 134.5% efficiency |   17 ns/op
Workers:  8 ->    96.10 M ops/sec |   9.2x speedup | 114.4% efficiency |   10 ns/op
Workers: 16 ->   161.39 M ops/sec |  15.4x speedup |  96.1% efficiency |    6 ns/op
Workers: 32 ->   198.18 M ops/sec |  18.9x speedup |  59.0% efficiency |    5 ns/op

These benchmarks demonstrate zbmd's low-latency actor system with sub-microsecond message passing, efficient bounded queues, and strong multi-core scaling up to 32 workers. The GPU benchmarks show excellent throughput scaling with larger workloads, achieving over 33 TFLOPS on vector addition operations.