webkernel/config
Benchmark & Performance Profiling
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Measure cold CLI access, a new key in a loaded section, a new section, PHP-FPM APCu access, full boot and repeated lookups separately. The target is 90 µs or less for the first keyed config() call; current cold CLI measurements are higher.
Measurement boundaries
| Measurement | Included work |
|---|---|
| Missing or stale cache | Discovery, source execution, compilation, cache write and lookup |
| Cold CLI, first keyed access | Read and decode one section file, then resolve the requested key; freshness validation is deferred until shutdown |
| New key, loaded section | Traverse that section's in-memory tree once and memoize the key |
| PHP-FPM, warm section | Stat one section file and fetch its decoded tree from APCu, then resolve the requested key |
| PHP-FPM, cold section | Read and decode the section file, then place its decoded tree in APCu for later requests |
Full Config::boot() | Read compiled PHP cache, compare inputs, check filesystem metadata and load all values |
| Subsequent access | In-memory lookup |
config_path() | Configured path access and optional concatenation |
Do not call Config::boot() or read configuration before timing a cold keyed access. Doing so excludes section loading. Measure a new key in an already loaded section separately from a key in a new section. In PHP-FPM, measure cold and APCu-warm section access in separate requests. Time Config::boot() and shutdown freshness work separately.
Example
Run this after the application's Composer autoloader has been required, before any configuration access:
hrtime(true);
$start = hrtime(true);
$value = config('paths.app');
$first_end = hrtime(true);
config('paths.app');
$second_end = hrtime(true);
$iterations = 1_000_000;
$loop_start = hrtime(true);
for ($index = 0; $index < $iterations; $index++) {
config('paths.app');
}
$loop_end = hrtime(true);
printf("First access: %.3f µs\n", ($first_end - $start) / 1_000);
printf("Second access: %.3f µs\n", ($second_end - $first_end) / 1_000);
printf("Repeated mean: %.3f µs\n", ($loop_end - $loop_start) / $iterations / 1_000);The repeated mean includes loop overhead. Print values after timing, and confirm the requested key exists. A missing key exercises the fallback path. A fresh CLI process cannot reuse its process memory; its disk-cache timing differs from later PHP-FPM requests that share APCu. Include process startup and shutdown separately when measuring command wall time.
OPcache and filesystem conditions
Record PHP version, SAPI, OPcache settings, whether bytecode is warm, source count, filesystem type, and whether the compiled cache was current. Performance measurements should enable OPcache. A fresh CLI process with opcache.enable_cli=1 still pays initial bytecode compilation; it does not represent a warmed PHP worker.
Use multiple runs and report their spread. An isolated first-call sample is sensitive to scheduling and filesystem state. A fast repeated mean does not establish the first-call budget.