refactor(root): introduce Metrics, perf, Runner and Reporter (#15)

Author: pyk

src/Metrics.zig

@@ -0,0 +1,41 @@
+///////////////////////////////////////////////////////////////////////////////
+// Meta
+
+/// The identifier string for the benchmark
+name: []const u8,
+/// Total number of measurement samples collected
+samples: usize,
+
+///////////////////////////////////////////////////////////////////////////////
+// Time
+
+/// Minimum execution time per operation (nanoseconds)
+min_ns: f64,
+/// Maximum execution time per operation (nanoseconds)
+max_ns: f64,
+/// Mean execution time (nanoseconds)
+mean_ns: f64,
+/// Median execution time (nanoseconds)
+median_ns: f64,
+/// Standard deviation of the execution time
+std_dev_ns: f64,
+
+///////////////////////////////////////////////////////////////////////////////
+// Throughput
+
+/// Calculated operations per second
+ops_sec: f64,
+/// Data throughput in MB/s (populated if `bytes_per_op` > 0)
+mb_sec: f64,
+
+///////////////////////////////////////////////////////////////////////////////
+// Hardware (Linux only, null otherwise)
+
+/// Average CPU cycles per operation
+cycles: ?f64 = null,
+/// Average CPU instructions executed per operation
+instructions: ?f64 = null,
+/// Instructions Per Cycle (efficiency ratio)
+ipc: ?f64 = null,
+/// Average cache misses per operation
+cache_misses: ?f64 = null,

src/Perf.test.zig

@@ -0,0 +1,34 @@
+const std = @import("std");
+const testing = std.testing;
+
+const Runner = @import("Runner.zig");
+const Reporter = @import("Reporter.zig");
+
+fn fibNaive(n: u64) u64 {
+    if (n <= 1) return n;
+    return fibNaive(n - 1) + fibNaive(n - 2);
+}
+
+fn fibIterative(n: u64) u64 {
+    if (n == 0) return 0;
+    var a: u64 = 0;
+    var b: u64 = 1;
+    for (2..n + 1) |_| {
+        const c = a + b;
+        a = b;
+        b = c;
+    }
+    return b;
+}
+
+test "report fib" {
+    const allocator = testing.allocator;
+    const opts = Runner.Options{
+        .sample_size = 100,
+        .warmup_iters = 3,
+    };
+    const m_naive = try Runner.run(allocator, "fibNaive", fibNaive, .{@as(u64, 20)}, opts);
+    const m_iter = try Runner.run(allocator, "fibIterative", fibIterative, .{@as(u64, 20)}, opts);
+
+    try Reporter.report(.{ .metrics = &.{ m_naive, m_iter }, .baseline_index = 0 });
+}