ubuntu20 use mpm_event

apache2 默认使用 mpm_prefork

切换为 mpm_event steps:

sudo a2dismod apache2
sudo a2dismod php7.4
suod a2dismod mpm_prefork

# 未安装php-fpm：
sudo apt-get install php7.4-fpm
systemctl enable php7.4-fpm
systemctl start php7.4-fpm

a2enmod mpm_event
a2enmod proxy_fcgi
a2enconf php7.4-fpm

systemctl start apache2