wa (waiting time) from top command is big


My top command shows me sometimes a big (80-90% or more) wa indicator. So this means my processor waits a LOT for I/O operations.
I/O operations mean writting and reading from hard disk ?

How can I see in realtime a list with processes / commands that make that waiting time so big ?

I mean I want to get a list with the processes that write to hard disk the most in that moment (measured in kbytes/s or whatever). So I can now what to kill / modify for that waiting time to cool.

Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

Processes in waiting state are denoted as 'D' state, they shown in top or ps output.
Since I/O operations flies through pageCache, You can't identify process's writing speed.
You can attach to such process with debugger and count every read/write syscall, but then, You will count all I/O, not hdd only.
BTW: check for swap usage, maybe You short at RAM?
vmstat 1 # si, so columns
softexp23Author Commented:

The LinuxQuestions.org guys offered me this response:

You'll need a (very) recent kernel with TASKSTATS - there is also a iotop.py out there if you want to have a quick search.

That's what I needed.

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today

From novice to tech pro — start learning today.