ph-string-dot-hot — string .= vs implode
Claim
Measured on this machine: primary hot case str_dot ratio before/after ~2.54× (faster after). Default severity stays off. Do not escalate to error from this fill alone.
How measured
- Harness:
packages/phpperf/examples/bench/evidence_ph001_ph003.php - Protocol: warm=3; median of 9 rounds; GC/collect where applicable
- Raw lines:
ph-string-dot-hot.jsonl
Runtime (this evidence file)
| Field | Value |
|---|---|
| When | 2026-10-23 Asia/Shanghai (machine clock; JSONL ts is UTC) |
| Toolchain | PHP 8.5.12 |
Median after (implode) | 0.319334 ms (ops=50000, ratio=1.000000) |
Median before (str_dot) | 0.811167 ms (ops=50000, ratio=2.540184) |
Median after (small_implode) | 0.000375 ms (ops=100, ratio=1.000000) |
Median before (small_str_dot) | 0.000917 ms (ops=100, ratio=2.445333) |
| Primary ratio before/after | ~2.54× (str_dot) |
Direction and absolute ms are N/machine/opt-sensitive. Re-run the harness after toolchain or machine changes.
Lint mapping
phpperf-lint ph-string-dot-hot default stays off. Escalate recommended: no.
Limits
- Microbench; not an app profile.
- Small-N rows may sit near timer noise; prefer hot (non-small) cases for ratio claims.
- I/O rules (print/echo/puts/writeln) discard to
/dev/null— env-dependent.