real_comparison/
real_comparison.rs

1//! Real algorithm comparison examples
2
3use hft_benchmarks::*;
4
5// Two different ways to sum numbers
6fn sum_with_loop(n: u32) -> u32 {
7    let mut sum = 0;
8    for i in 0..n {
9        sum += i;
10    }
11    sum
12}
13
14fn sum_with_formula(n: u32) -> u32 {
15    n * (n - 1) / 2
16}
17
18// Two different ways to check if number is even
19fn is_even_modulo(n: u32) -> bool {
20    n % 2 == 0
21}
22
23fn is_even_bitwise(n: u32) -> bool {
24    n & 1 == 0
25}
26
27fn main() {
28    quick_calibrate_tsc_frequency();
29    
30    println!("🔬 Real Algorithm Comparisons\n");
31    
32    // Test 1: Sum algorithms
33    println!("=== Sum Algorithms (n=100) ===");
34    
35    let loop_perf = SimpleBench::new("sum_with_loop")
36        .bench(10000, || sum_with_loop(100))
37        .analyze();
38    
39    let formula_perf = SimpleBench::new("sum_with_formula")
40        .bench(10000, || sum_with_formula(100))
41        .analyze();
42    
43    println!("Loop method:    mean={}ns, P99={}ns", loop_perf.mean, loop_perf.p99);
44    println!("Formula method: mean={}ns, P99={}ns", formula_perf.mean, formula_perf.p99);
45    
46    if formula_perf.mean < loop_perf.mean {
47        let improvement = (loop_perf.mean as f64 / formula_perf.mean as f64 - 1.0) * 100.0;
48        println!("✅ Formula is {:.1}% faster", improvement);
49    } else if loop_perf.mean < formula_perf.mean {
50        let degradation = (formula_perf.mean as f64 / loop_perf.mean as f64 - 1.0) * 100.0;
51        println!("⚠️  Loop is {:.1}% faster", degradation);
52    } else {
53        println!("🤝 Both methods perform similarly");
54    }
55    
56    // Test 2: Even number check
57    println!("\n=== Even Number Check ===");
58    
59    let modulo_perf = SimpleBench::new("is_even_modulo")
60        .bench(10000, || is_even_modulo(12345))
61        .analyze();
62    
63    let bitwise_perf = SimpleBench::new("is_even_bitwise")
64        .bench(10000, || is_even_bitwise(12345))
65        .analyze();
66    
67    println!("Modulo method:  mean={}ns, P99={}ns", modulo_perf.mean, modulo_perf.p99);
68    println!("Bitwise method: mean={}ns, P99={}ns", bitwise_perf.mean, bitwise_perf.p99);
69    
70    if bitwise_perf.mean < modulo_perf.mean {
71        let improvement = (modulo_perf.mean as f64 / bitwise_perf.mean as f64 - 1.0) * 100.0;
72        println!("✅ Bitwise is {:.1}% faster", improvement);
73    } else if modulo_perf.mean < bitwise_perf.mean {
74        let degradation = (bitwise_perf.mean as f64 / modulo_perf.mean as f64 - 1.0) * 100.0;
75        println!("⚠️  Modulo is {:.1}% faster", degradation);
76    } else {
77        println!("🤝 Both methods perform similarly");
78    }
79    
80    // Test 3: Vector vs Array
81    println!("\n=== Vector vs Array Access ===");
82    
83    let vec_data = vec![1, 2, 3, 4, 5];
84    let array_data = [1, 2, 3, 4, 5];
85    
86    let vec_perf = SimpleBench::new("vector_access")
87        .bench(10000, || {
88            let sum = vec_data.iter().sum::<i32>();
89            std::hint::black_box(sum);
90        })
91        .analyze();
92    
93    let array_perf = SimpleBench::new("array_access")
94        .bench(10000, || {
95            let sum = array_data.iter().sum::<i32>();
96            std::hint::black_box(sum);
97        })
98        .analyze();
99    
100    println!("Vector access: mean={}ns, P99={}ns", vec_perf.mean, vec_perf.p99);
101    println!("Array access:  mean={}ns, P99={}ns", array_perf.mean, array_perf.p99);
102    
103    if array_perf.mean < vec_perf.mean {
104        let improvement = (vec_perf.mean as f64 / array_perf.mean as f64 - 1.0) * 100.0;
105        println!("✅ Array is {:.1}% faster", improvement);
106    } else if vec_perf.mean < array_perf.mean {
107        let degradation = (array_perf.mean as f64 / vec_perf.mean as f64 - 1.0) * 100.0;
108        println!("⚠️  Vector is {:.1}% faster", degradation);
109    } else {
110        println!("🤝 Both perform similarly");
111    }
112    
113    println!("\n💡 Note: Results may vary between runs due to:");
114    println!("   - CPU cache state");
115    println!("   - System load");
116    println!("   - Compiler optimizations");
117    println!("   - Memory layout");
118}
real_comparison/real_comparison.rs

real_comparison/
real_comparison.rs
