How is i/o Wait time Calculated?

[nick_r_ross]

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

[michael_kopp · Accepted solution]

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

[michael_p]

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?