fix: increase JFR sampling frequency and make Workload exercise functions harder

- Set jdk.ExecutionSample#period=1ms (default was 10ms) so JFR captures
  samples from shorter-running programs
- Workload.main now runs 1000 rounds with larger inputs so JFR can
  capture method-level CPU samples (repeatString with O(n²) concat
  dominates ~75% of samples)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: misrasaurabh1

codeflash/languages/java/tracer.py

@@ -122,7 +122,12 @@ def create_tracer_config(
 
     def build_jfr_env(self, jfr_file: Path) -> dict[str, str]:
         env = os.environ.copy()
-        jfr_opts = f"-XX:StartFlightRecording=filename={jfr_file.resolve()},settings=profile,dumponexit=true"
+        # Use profile settings with increased sampling frequency (1ms instead of default 10ms)
+        # This captures more samples for short-running programs
+        jfr_opts = (
+            f"-XX:StartFlightRecording=filename={jfr_file.resolve()},settings=profile,dumponexit=true"
+            ",jdk.ExecutionSample#period=1ms"
+        )
         existing = env.get("JAVA_TOOL_OPTIONS", "")
         env["JAVA_TOOL_OPTIONS"] = f"{existing} {jfr_opts}".strip()
         return env

tests/test_languages/fixtures/java_tracer_e2e/src/main/java/com/example/Workload.java

@@ -36,20 +36,30 @@ public int instanceMethod(int x, int y) {
     }
 
     public static void main(String[] args) {
-        // Exercise the methods so the tracer can capture invocations
-        System.out.println("computeSum(100) = " + computeSum(100));
-        System.out.println("computeSum(50) = " + computeSum(50));
+        // Run methods with large inputs so JFR can capture CPU samples.
+        // Small inputs finish too fast (<1ms) for JFR's 10ms sampling interval.
+        for (int round = 0; round < 1000; round++) {
+            computeSum(100_000);
+            repeatString("hello world ", 1000);
+
+            List<Integer> nums = new ArrayList<>();
+            for (int i = 1; i <= 10_000; i++) nums.add(i);
+            filterEvens(nums);
 
+            Workload w = new Workload();
+            w.instanceMethod(100_000, 42);
+        }
+
+        // Also call with small inputs for variety in traced args
+        System.out.println("computeSum(100) = " + computeSum(100));
         System.out.println("repeatString(\"ab\", 3) = " + repeatString("ab", 3));
-        System.out.println("repeatString(\"x\", 5) = " + repeatString("x", 5));
 
-        List<Integer> nums = new ArrayList<>();
-        for (int i = 1; i <= 10; i++) nums.add(i);
-        System.out.println("filterEvens(1..10) = " + filterEvens(nums));
+        List<Integer> small = new ArrayList<>();
+        for (int i = 1; i <= 10; i++) small.add(i);
+        System.out.println("filterEvens(1..10) = " + filterEvens(small));
 
         Workload w = new Workload();
         System.out.println("instanceMethod(5, 3) = " + w.instanceMethod(5, 3));
-        System.out.println("instanceMethod(10, 2) = " + w.instanceMethod(10, 2));
 
         System.out.println("Workload complete.");
     }