Tune PHP-FPM Performance on Gentoo Linux

Estimate pm.max_children

ps -ylC php-fpm --no-headers | awk '{sum+=$8} END {print sum/NR/1024 " MB avg"}'
# Divide available RAM (minus OS+DB) by average size

Recommended dynamic settings

pm = dynamic
pm.max_children      = 50
pm.start_servers     = 10
pm.min_spare_servers = 5
pm.max_spare_servers = 20
pm.max_requests      = 500
pm.process_idle_timeout = 10s

Slow log

request_slowlog_timeout = 5s
slowlog = /var/log/php-fpm/www-slow.log

tail -f /var/log/php-fpm/www-slow.log

Status endpoint

pm.status_path = /fpm-status

location /fpm-status {
    allow 127.0.0.1; deny all;
    fastcgi_pass unix:/run/php-fpm/www.sock;
    include fastcgi_params;
    fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
}