topic Re: How is i/o Wait time Calculated? in Open Q&A

How is i/o Wait time Calculated?

nick_r_ross — Thu, 21 Dec 2023 11:45:44 GMT

I'm familiar with AppMon's calculation of i/o:

i/o = Response Time - CPU - Sync - Runtime Suspension - Wait

However, this is calculated on a per PurePath basis.

I am working with a customer and saw the following CPU graph. In this case I wasn't able to articulate precisely what was causing this high I/O Wait time.

It is an Amazon Linux host.

Any help/descriptions would be greatly appreciated.

Thanks

Nick

Re: How is i/o Wait time Calculated?

michael_kopp — Tue, 07 Mar 2017 12:49:09 GMT

This is the I/O wait as reported by the operating system, it does not come from the agent or purepath.

See https://linux.die.net/man/1/atop

Re: How is i/o Wait time Calculated?

michael_p — Mon, 15 Apr 2019 14:39:31 GMT

Hi @Michael K., we experience the same alert. Do you think that the status "CPU Saturation" is correct in case of IOWait - which is - as far as I know - a state of Idle. That said - additional workload could still be accepted by the CPU - or am I wrong?