Attempting to profile MySQL server with Intel® VTune™ Amplifier's user-mode sampling collector produces unexpected behavior such as empty results or "access denied" errors:
mysqlslap: Error when connecting to server: Access denied for user 'root'@'localhost' (using password: NO)
In general, you need to use a benchmark to keep MySQL server busy for profiling purposes, otherwise you will end up with an empty result. Further, the user-mode sampling collector can fail when MySQL server starts from a different account than VTune Amplifier is being run from (e.g. MySQL server starts from the "mysql" user account, but VTune Amplifier is being run as the "root" user).
Shut down the mysql process if it exists, then start mySQL from the user account you will be running VTune Amplifier under (in this example, "root"). Be sure to use a benchmark (in this example, mysqlslap) to ensure that there is activity to profile.
mysqld_safe --user=root --skip-grant-tables --skip-networking & mysqlslap --user=root --auto-generate-sql --iterations=10000 & amplxe-cl --collect hotspots --duration 30 --target-pid 12345