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

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- 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>
This commit is contained in:
misrasaurabh1 2026-03-19 23:48:36 -07:00
parent 803fb64f05
commit 13dae81bd2
2 changed files with 24 additions and 9 deletions
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7
codeflash/languages/java/tracer.py
View file

@ -122,7 +122,12 @@ class JavaTracer:
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

26
tests/test_languages/fixtures/java_tracer_e2e/src/main/java/com/example/Workload.java
View file

@ -36,20 +36,30 @@ public class Workload {
}
public static void main(String[] args) {
// Exercise the methods so the tracer can capture invocations
// 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("computeSum(50) = " + computeSum(50));
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.");
}