On Tue, Mar 25, 2008 at 12:00 PM, CHAPLIN, JAMES (CTR) <[EMAIL PROTECTED]> wrote: > We are using RHEL 5.0 & 4.5 (pending if using Oracle or not). So I am > assuming the information form PERFKIT is the best measure of CPU Usage?
That probably means you have a 2.6 kernel and your CPU usage is already broken up into more components than the ones you mention. Maybe your tools are based on 2.4 kernels and don't show you all. Performance Toolkit may be able to tell you how much the virtual machine was using, but not why or how. AFAIK the technology to feed it with information about Linux internals is neither strategic nor attractive. > I am trying to understand the "waiting for I/O" value of CPU, is this > CPU unable to process other work? The Linux perception is that it is waiting for I/O. But only the VM data can reveal whether that is really true. I can certainly think of situations where lack of CPU or memory on z/VM will make Linux think it is waiting for the disk I/O. That's not a problem for Linux because it really does not need to know these details (virtualization is also about hiding details from the guest). But it is a problem for the performance analyst who wants to tune his Linux on z/VM configuration. That's why we claim you need to see both sides of the equation. Rob -- Rob van der Heij Velocity Software GmbH http://velocitysoftware.com/ ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390
