From 502479677b70ddaef7af7e6508f83f2a1c33cfa9 Mon Sep 17 00:00:00 2001
From: dailz <dailz@192.168.1.254>
Date: Fri, 5 Jun 2026 17:28:57 +0800
Subject: [PATCH] fix(bench): warn when clear_file_cache fails instead of
 silently skipping cold benchmarks (closes #41)

---
 crates/bench/src/suites/startup.rs | 76 ++++++++++++++++++------------
 1 file changed, 45 insertions(+), 31 deletions(-)

diff --git a/crates/bench/src/suites/startup.rs b/crates/bench/src/suites/startup.rs
index 94edebf..f463502 100644
--- a/crates/bench/src/suites/startup.rs
+++ b/crates/bench/src/suites/startup.rs
@@ -40,35 +40,42 @@ pub fn run(config: &BenchConfig) -> Vec<BenchmarkResult> {
     ));
 
     if !config.quick_mode {
-        if MetricsCollector::clear_file_cache(&config.test_file).is_ok() {
-            results.extend(bench_cold_open::<MmapReaderPlain>("mmap", "plain", config));
-            results.extend(bench_cold_open::<MmapReaderSequential>(
-                "mmap",
-                "sequential",
-                config,
-            ));
-            results.extend(bench_cold_open::<MmapReaderRandom>(
-                "mmap", "random", config,
-            ));
-            results.extend(bench_cold_open::<MmapReaderPopulate>(
-                "mmap", "populate", config,
-            ));
-            results.extend(bench_cold_open::<MmapReaderPhaseAware>(
-                "mmap",
-                "phase_aware",
-                config,
-            ));
-            results.extend(bench_cold_open::<PreadReaderPlain>(
-                "pread", "plain", config,
-            ));
-            results.extend(bench_cold_open::<PreadReaderRandom>(
-                "pread", "random", config,
-            ));
-            results.extend(bench_cold_open::<PreadReaderSequential>(
-                "pread",
-                "sequential",
-                config,
-            ));
+        match MetricsCollector::clear_file_cache(&config.test_file) {
+            Ok(()) => {
+                results.extend(bench_cold_open::<MmapReaderPlain>("mmap", "plain", config));
+                results.extend(bench_cold_open::<MmapReaderSequential>(
+                    "mmap",
+                    "sequential",
+                    config,
+                ));
+                results.extend(bench_cold_open::<MmapReaderRandom>(
+                    "mmap", "random", config,
+                ));
+                results.extend(bench_cold_open::<MmapReaderPopulate>(
+                    "mmap", "populate", config,
+                ));
+                results.extend(bench_cold_open::<MmapReaderPhaseAware>(
+                    "mmap",
+                    "phase_aware",
+                    config,
+                ));
+                results.extend(bench_cold_open::<PreadReaderPlain>(
+                    "pread", "plain", config,
+                ));
+                results.extend(bench_cold_open::<PreadReaderRandom>(
+                    "pread", "random", config,
+                ));
+                results.extend(bench_cold_open::<PreadReaderSequential>(
+                    "pread",
+                    "sequential",
+                    config,
+                ));
+            }
+            Err(e) => {
+                eprintln!(
+                    "WARNING: Failed to clear file cache; skipping cold startup benchmarks because results would not be cold: {e}"
+                );
+            }
         }
     }
 
@@ -88,8 +95,15 @@ fn bench_cold_open<B: FileReaderBackend>(
     variant: &str,
     config: &BenchConfig,
 ) -> Vec<BenchmarkResult> {
-    let _ = MetricsCollector::clear_file_cache(&config.test_file);
-    open_and_measure::<B>(backend, variant, &config.test_file, "cold_open")
+    match MetricsCollector::clear_file_cache(&config.test_file) {
+        Ok(()) => open_and_measure::<B>(backend, variant, &config.test_file, "cold_open"),
+        Err(e) => {
+            eprintln!(
+                "WARNING: Failed to clear file cache for {backend}/{variant}; skipping cold benchmark: {e}"
+            );
+            Vec::new()
+        }
+    }
 }
 
 fn open_and_measure<B: FileReaderBackend>(