Super User is a question and answer site for computer enthusiasts and power users. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I am referring to the Linux top command. If it indicates 10.4% was spent on wa, does that mean 10.4% CPU was available for other processes?

top - 09:40:45 up 178 days, 34 min,  1 user,  load average: 0.32, 0.43, 0.42
Tasks: 173 total,   1 running, 172 sleeping,   0 stopped,   0 zombie
Cpu(s): 1.3%us,  1.1%sy,  0.0%ni, 87.2%id,  10.4%wa,  0.0%hi,  0.0%si,  0.0%st
share|improve this question

migrated from Apr 22 '11 at 15:10

This question came from our site for professional and enthusiast programmers.

up vote 1 down vote accepted

wa is the time the CPU is waiting for I/O to complete. 87.2%id is the amount of CPU spends in idle, and therefore would be available for other processes.

share|improve this answer
Not entirely true, if I have understood your answer correctly. Both wa (IO wait) and id (idle) time are available for other processes to use. – Benjamin Goodacre Oct 29 '14 at 11:17

The percentage expressed in wa (IOwait) does not convey idle time on the CPU. It could indeed be idle or it could be being used by another process.

The percentage expressed in id (idle) does not express total idle time either, this is idle-time not otherwise allocated. The percentage of CPU time available for other processes can be expressed as 100 - us (user) - sy (system) .

share|improve this answer

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .