On Tue, 27 Sep 2011 19:44:02 +0200 Rob van der Heij wrote: > The probably refer to "load average" which is the number of processes > that run or would be able to run. The easy math is that for an N-way > guest, the load average larger than N means that processes wait to get > CPU resources. Since CPU resources are often the most expensive part, > it's good to wait for CPU rather than something else. If your load > average is lower than N, there's no CPU waiting as far as Linux is > concerned.
Note that this is the *Unix* definition of loadavg - not the Linux definition. Unfortunately one of those of old saws that has been handed down through the generations. Software designers have been known to use this metric to (dynamically) limit connections to their software - database for example. Bad idea. Mark gave the correct definition. Note that processes in uninterruptible sleep (state "D") comprise more than just those waiting on (disk) I/O to complete as is commonly asumed. HTTP servers parking threads as "D" then forgetting about them is not unknown. Makes an awful mess of the loadavg - and any software using the metric incorrectly. Mind you, it's hard to think of ways to use it correctly ... Almost as meaningless is %wa. Shane ... ---------------------------------------------------------------------- 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 ---------------------------------------------------------------------- For more information on Linux on System z, visit http://wiki.linuxvm.org/
