<?php
echo "<!--\n";
echo "Дата генерации: " . date('r') . "\n";
echo "Время генерации: " . timer_read('page') . " ms\n";
echo "Использовано памяти: " . round(memory_get_usage() / 1024 / 1024, 2) . " mb\n";
echo "-->\n";
?>

<?php echo '<!-- ' . date('r') . ' | ' . timer_read('page') . ' ms | ' . round(memory_get_usage() / 1024 / 1024, 2) . ' mb -->'; ?>

Drupal 6, Drupal 7