Set up xdebug on your machine

cat /usr/local/etc/php/conf.d/docker-php-ext-xdebug.ini
zend_extension=xdebug

cat /usr/local/etc/php/conf.d/xdebug.ini
xdebug.mode=profile
;debug,develop

xdebug.output_dir=/var/www/html/site.ext/ramon
xdebug.profiler_output_name=cachegrind.out.%p.%t
xdebug.use_compression=false
xdebug.start_with_request=yes

xdebug.discover_client_host=false
xdebug.client_host=host.docker.internal
xdebug.client_port=9000
;xdebug.log=/tmp/xdebug.log
xdebug.log=/var/www/html/site.ext/ramon

Now use that /ramon directory to check the cachegrind.out files

Command:

qcachegrind