ps aux|grep php-fpm

root       378  0.0  0.2  31200  3044 ?        Ss   18:10   0:00 php-fpm: master process (/usr/local/php7/etc/php-fpm.conf)                                                                      nobody     379  0.0  0.4  31264  4752 ?        S    18:10   0:00 php-fpm: pool www                                                                                                               nobody     380  0.0  0.4  31264  4752 ?        S    18:10   0:00 php-fpm: pool www                                                                                                               root      6554  0.0  0.0   6048   804 pts/0    S+   18:37   0:00 grep php-fpm

kill -USR2 378