Initialization

How to initialize and configure the Blitz thread pool.

Basic Initialization

const blitz = @import("blitz");

pub fn main() !void {
    // Initialize with automatic thread detection
    try blitz.init();
    defer blitz.deinit();

    // Now use parallel operations...
}

Custom Configuration

try blitz.initWithConfig(.{
    // Number of background worker threads
    // Default: CPU count - 1 (main thread also participates)
    .background_worker_count = 8,
});
defer blitz.deinit();

Query Runtime Status

// Check if initialized
if (blitz.isInitialized()) {
    std.debug.print("Pool is ready\n", .{});
}

// Get worker count (including main thread)
const workers = blitz.numWorkers();
std.debug.print("Running with {} workers\n", .{workers});

Grain Size Configuration

Control minimum chunk size for parallel operations:

// Get current grain size (default: 65536)
const current = blitz.getGrainSize();

// Set custom grain size
blitz.setGrainSize(2048);

// Reset to default
blitz.setGrainSize(blitz.DEFAULT_GRAIN_SIZE); // 65536

The default grain size (DEFAULT_GRAIN_SIZE = 65536) works well for most workloads. Reduce it for expensive per-element operations; increase it for trivial operations.

Initialization is Required

Blitz does not auto-initialize. You must call init() before using parallel operations:

// Correct usage
try blitz.init();
defer blitz.deinit();
const sum = blitz.iter(i64, data).sum();

Calling initWithConfig() on an already-initialized pool returns error.AlreadyInitialized.

Pool Statistics

// Get execution stats
const stats = blitz.getStats();
std.debug.print("Executed: {}, Stolen: {}\n", .{ stats.executed, stats.stolen });

// Reset stats
blitz.resetStats();

Thread Count Guidelines

Workload Type	Recommended Threads
CPU-bound (compute)	CPU count
Memory-bound (copy, scan)	CPU count / 2
Mixed	CPU count - 1
I/O-bound	Not ideal for Blitz

Example: Production Setup

pub fn initBlitz() !void {
    const cpu_count = std.Thread.getCpuCount() catch 4;

    try blitz.initWithConfig(.{
        // Leave 1 core for OS and other tasks
        .background_worker_count = @max(1, cpu_count - 2),
    });
}

pub fn main() !void {
    try initBlitz();
    defer blitz.deinit();

    // Application code...
}