Original question (abridged):
>Both "top" and "xmeter" show CPU utilization as 100%, but vmstat shows about
>80% idle. The difference seems to be that top (and I assume xmeter) class
>"iowait" cpu usage as busy, whereas vmstat considers it idle.
Iowait means the CPU is idle, but there are processes waiting on short-term IO
(usually disks) which will run just as soon as the IO is finished. If another
CPU-bound job came along it would run, but the disk system is flat out.
Basically, the system is io-bound and has CPU cycles to spare.
This is not really an error, and is probably unavoidable in database
applications. Actually, I kind of like "iowait" as a concept, and can
understand how the different programs treat it differently.
A couple of people also mentioned "sar" as a better tool than vmstat for
Thanks to those that responded.
This archive was generated by hypermail 2.1.2 : Fri Sep 28 2001 - 23:10:35 CDT