pgrep is a cool tool that shows all pids matching a given pattern, like
# pgrep -fl mysql

You can use it with #top to monitor memory usage and other stuff. Modern tools like #iotop are task/thread based and pgrep is not very useful in this case, because you are not tracking the IO made by subtasks.

We patched pgrep to print out all task/thread id, and we’re glad that our patch was merged in the trunk (available in Fedora 19)!
Just use the -w flag to list all threads (lightweight processes)
# pgrep -flw mysql

You can otherwise take that infos with the following
egrep -rl mysql /proc/[0-9]*/task/[0-9]*/cmdline | cut -d\/ -f 5