⚡ Optimize MutedKeywordFilter string cloning

home-mixer/benches/muted_keywords_perf.rs

@@ -0,0 +1,76 @@
+// Usage: rustc -O home-mixer/benches/muted_keywords_perf.rs && ./muted_keywords_perf
+
+use std::time::Instant;
+
+// Simulate the heavy operation of tokenizing/processing a string
+fn simulate_process(s: &str) -> usize {
+    s.len()
+}
+
+// The "Before" implementation: Clones the vector
+fn implementation_before(keywords: &Vec<String>) -> usize {
+    // OLD CODE: Cloned the vector
+    let muted_keywords = keywords.clone();
+
+    if muted_keywords.is_empty() {
+        return 0;
+    }
+
+    let processed = muted_keywords.iter().map(|k| simulate_process(k));
+    processed.sum()
+}
+
+// The "After" implementation: Uses a reference
+fn implementation_after(keywords: &Vec<String>) -> usize {
+    // NEW CODE: Uses reference
+    let muted_keywords = keywords;
+
+    if muted_keywords.is_empty() {
+        return 0;
+    }
+
+    let processed = muted_keywords.iter().map(|k| simulate_process(k));
+    processed.sum()
+}
+
+fn main() {
+    // Setup data
+    let keyword_count = 100;
+    let iterations = 1_000_000;
+    let keywords: Vec<String> = (0..keyword_count).map(|i| format!("keyword_{}", i)).collect();
+
+    println!("Running benchmark with {} keywords over {} iterations...", keyword_count, iterations);
+
+    // Warmup
+    for _ in 0..1000 {
+        implementation_before(&keywords);
+        implementation_after(&keywords);
+    }
+
+    // Measure Before
+    let start_before = Instant::now();
+    let mut sum_before = 0;
+    for _ in 0..iterations {
+        sum_before += implementation_before(&keywords);
+    }
+    let duration_before = start_before.elapsed();
+
+    // Measure After
+    let start_after = Instant::now();
+    let mut sum_after = 0;
+    for _ in 0..iterations {
+        sum_after += implementation_after(&keywords);
+    }
+    let duration_after = start_after.elapsed();
+
+    // Verify correctness
+    assert_eq!(sum_before, sum_after, "Implementations produced different results!");
+
+    // Report
+    println!("\nResults:");
+    println!("Before (Clone):     {:.4} seconds", duration_before.as_secs_f64());
+    println!("After (Reference):  {:.4} seconds", duration_after.as_secs_f64());
+
+    let speedup = duration_before.as_secs_f64() / duration_after.as_secs_f64();
+    println!("Speedup:            {:.2}x", speedup);
+}

home-mixer/filters/muted_keyword_filter.rs

@@ -26,7 +26,7 @@ impl Filter<ScoredPostsQuery, PostCandidate> for MutedKeywordFilter {
         query: &ScoredPostsQuery,
         candidates: Vec<PostCandidate>,
     ) -> Result<FilterResult<PostCandidate>, String> {
-        let muted_keywords = query.user_features.muted_keywords.clone();
+        let muted_keywords = &query.user_features.muted_keywords;
 
         if muted_keywords.is_empty() {
             return Ok(FilterResult {