Convert SPX format to trace event

convert-spx-to-trace.php

<?php

// Usage: php convert-spx-to-trace.php input.dms > foo-trace.json

[, $file] = $argv;

$data = file($file);

$functions = [];
$events = [];
$type = null;
foreach ($data as $line) {
    $line = rtrim($line);

    if ($line === '[events]') {
        $type = 'event';
        continue;
    }

    if ($line === '[functions]') {
        $type = 'function';
        continue;
    }

    if ($type === 'event') {
        $events[] = explode(' ', $line);
    }

    if ($type === 'function') {
        $functions[] = $line;
    }
}

$info = [];
foreach ($events as $eventInfo) {
    $fnIndex = (int) $eventInfo[0];
    $eventType = (int) $eventInfo[1];
    $m1 = (float) $eventInfo[2];

    // To have the right time unit
    $m1 = $m1 / 1000;

    $info[] = [
        'ph' => $eventType === 1 ? 'B' : 'E',
        // We assume that the first metrics is the wall time inc.
        'ts' => $m1,
        'name' => $functions[$fnIndex],
    ];
}

$trace = [
    'otherData' => [
        'buildTs' => time(),
    ],
    'displayTimeUnit' => 'ns',
    'traceEvents' => $info,
];

echo json_encode($trace, flags: JSON_THROW_ON_ERROR);