PHP后端性能监控与调优

PHP后端性能监控与调优

性能问题迟早会遇到。系统上线后随着用户量增长各种瓶颈就会暴露出来。今天说说PHP应用的性能监控和调优。

性能监控的第一步是测量。关键路径上加计时器。

```php
class PerformanceMonitor
{
private array $timers = [];
private array $results = [];

public function startTimer(string $name): void
{
$this->timers[$name] = microtime(true);
}

public function stopTimer(string $name): void
{
if (isset($this->timers[$name])) {
$duration = (microtime(true) - $this->timers[$name]) * 1000;
$this->results[] = ['name' => $name, 'duration_ms' => round($duration, 2)];
unset($this->timers[$name]);
}
}

public function getReport(): array
{
$totalTime = array_sum(array_column($this->results, 'duration_ms'));
return [
'total_time_ms' => round($totalTime, 2),
'breakdown' => $this->results,
'peak_memory_mb' => round(memory_get_peak_usage(true) / 1024 / 1024, 2),
];
}
}

$monitor = new PerformanceMonitor();

$monitor->startTimer('db_query');
usleep(200000);
$monitor->stopTimer('db_query');

$monitor->startTimer('data_process');
usleep(100000);
$monitor->stopTimer('data_process');

print_r($monitor->getReport());
?>

慢查询日志记录。

```php
function enableSlowQueryLog(PDO $pdo, float $threshold = 1.0): PDO
{
return $pdo;
}

class SlowQueryLogger
{
private float $threshold = 1.0;

public function log(string $sql, float $duration): void
{
if ($duration >= $this->threshold) {
$log = sprintf("[%s] 慢查询 %.4fs: %s\n", date('Y-m-d H:i:s'), $duration, $sql);
file_put_contents('/tmp/slow-queries.log', $log, FILE_APPEND);
}
}
}
?>

OPcache监控。

```php
function getOpcacheStatus(): array
{
if (!function_exists('opcache_get_status')) return ['error' => 'OPcache未启用'];

$status = opcache_get_status(false);
if ($status === false) return ['error' => '无法获取状态'];

$memory = $status['memory_usage'];
$stats = $status['opcache_statistics'];

return [
'memory_usage_percent' => round($memory['used_memory'] / ($memory['used_memory'] + $memory['free_memory']) * 100, 2),
'cached_files' => $stats['num_cached_scripts'],
'hit_rate' => round($stats['hits'] / ($stats['hits'] + $stats['misses']) * 100, 2),
];
}

print_r(getOpcacheStatus());
?>

JIT配置监控。

```php
function getJitStatus(): array
{
$status = opcache_get_status(false);
$jit = $status['jit'] ?? [];
return [
'enabled' => $jit['enabled'] ?? false,
'buffer_size' => ($jit['buffer_size'] ?? 0) / 1024 / 1024 . 'MB',
];
}
?>

性能优化要有的放矢。先用监控找出真正的瓶颈，再针对性地优化。数据库查询往往是最值得优化的地方，一条慢查询解决好了可能比一堆PHP优化更有效。