How do you find out how much time a system spends waiting for IO?

Question

Is there a linux command that allows you to see a processes IO wait time vs. CPU time? I'm trying to see whether some processes are IO-bound or CPU-bound.

Answer 1

I think iostat is the basic tool you want.

Answer 2

Have a look at iotop.

Answer 3

If you install the atsar package you can look at the system's CPU and I/O stats. Simply using top should give let you know if the a particular process is CPU or memory bound. I am not sure how you see the I/O stats for a particular process.

Answer 4

top (1) will show this information. You can specify a particular process ID with -p.

Answer 5

Try mpstat and look at %iowait.

[pdurbin@beamish ~]$ mpstat 1 5
Linux 2.6.18-128.1.10.el5 (beamish)    05/14/2009

03:25:27 PM  CPU   %user   %nice    %sys %iowait    %irq   %soft  %steal   %idle    intr/s
03:25:28 PM  all    0.00    0.00    0.00    0.00    0.00    0.00    0.00  100.00   1073.00
03:25:29 PM  all    0.25    0.00    0.50    0.00    0.00    0.25    0.00   99.00   1202.00
03:25:30 PM  all    1.50    0.00    0.00    0.00    0.00    0.00    0.00   98.50   1071.00
03:25:31 PM  all    0.25    0.00    0.00    0.00    0.00    0.00    0.00   99.75   1150.00
03:25:32 PM  all    0.25    0.00    0.00    0.00    0.00    0.00    0.00   99.75   1086.00
Average:     all    0.45    0.00    0.10    0.00    0.00    0.05    0.00   99.40   1116.40