fix(bench): regenerate growable file each iteration in truncate safety benchmarks (closes #44)

crates/bench/src/suites/rotation.rs

@@ -24,13 +24,14 @@ fn bench_truncate_safety_mmap(
     dir: &std::path::Path,
 ) -> Vec<BenchmarkResult> {
     let sub_dir = dir.join("trunc_mmap");
-    let path = data_gen::generate_growable_file(&sub_dir).expect("Failed to create file");
     let iterations: usize = if _config.quick_mode { 3 } else { 10 };
 
     let mut latencies = Vec::with_capacity(iterations);
     let mut sigbus_detected = 0usize;
 
     for _ in 0..iterations {
+        let path = data_gen::generate_growable_file(&sub_dir).expect("Failed to create file");
+
         mmap_reader::reset_sigbus_flag();
 
         let reader = MmapReaderPlain::open(&path).expect("Failed to open file");
@@ -48,12 +49,6 @@ fn bench_truncate_safety_mmap(
             sigbus_detected += 1;
         }
         reader.close();
-
-        let mut f = std::fs::File::create(&path).expect("Failed to recreate file");
-        use std::io::Write;
-        for i in 0..1000u64 {
-            writeln!(f, "restored line {i}").unwrap();
-        }
     }
 
     let rss = MetricsCollector::read_rss();
@@ -82,13 +77,14 @@ fn bench_truncate_safety_pread(
     dir: &std::path::Path,
 ) -> Vec<BenchmarkResult> {
     let sub_dir = dir.join("trunc_pread");
-    let path = data_gen::generate_growable_file(&sub_dir).expect("Failed to create file");
     let iterations: usize = if _config.quick_mode { 3 } else { 10 };
 
     let mut latencies = Vec::with_capacity(iterations);
     let mut error_count = 0usize;
 
     for _ in 0..iterations {
+        let path = data_gen::generate_growable_file(&sub_dir).expect("Failed to create file");
+
         let reader = PreadReaderPlain::open(&path).expect("Failed to open file");
         let original_size = reader.file_size();
 
@@ -104,12 +100,6 @@ fn bench_truncate_safety_pread(
             error_count += 1;
         }
         reader.close();
-
-        let mut f = std::fs::File::create(&path).expect("Failed to recreate file");
-        use std::io::Write;
-        for i in 0..1000u64 {
-            writeln!(f, "restored line {i}").unwrap();
-        }
     }
 
     let rss = MetricsCollector::read_rss();