kt-println-hot — println in loop
Status: measured
Claim
Per-iteration println to /dev/null is much slower than quiet loop + one println (~270× on Kotlin 2.4.21 / JDK 27).
How measured
-
Harness: EvidenceKt.kt
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N=20000
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Raw lines:
kt-println-hot.jsonl
Runtime (this evidence file)
| Field | Value |
|---|---|
| When | 2026-10-22 Asia/Shanghai (JSONL ts is UTC) |
| kotlin | 2.0.21 |
| jre | 21.0.12.1 |
Median before (println_in_loop) | 8.620792 ms |
Median after (println_once) | 0.031875 ms |
| ratio before/after | ~270× |
Lint mapping
kotlinperf-lint kt-println-hot: keep default; kit-local KT* only.
Limits
- Default stays off.