Date: Tue, 04 Apr 2000 22:49:52 +0200 From: Mattias Pantzare <pantzer@ludd.luth.se> To: Donn Miller <dmmiller@cvzoom.net> Cc: current@FreeBSD.ORG Subject: Re: Load average calculation? Message-ID: <200004042049.WAA06304@queeg.ludd.luth.se> In-Reply-To: Message from Donn Miller <dmmiller@cvzoom.net> of "Mon, 03 Apr 2000 16:26:03 EDT." <38E8FE5B.CD2FD3E6@cvzoom.net>
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> Patrick Mau wrote: > > > On all Unix-like systems I know, the load average is the average mumber > > of processes running during a given time interval. I can't see what use > > it may have to count load for _waiting_ processes. > > > > I/O load is not process load, if a process waits for I/O completion it does > > not use up its timeslice. > > I think we ought to re-examine the definition of load average. By > load, we mean an actual load on the cpu, and waiting processes aren't > really exerting a cpu load. So, by that reasoning I say waiting > processes don't count. The load average number is not a measure of the CPU load. It is a measure of _system_ load. Processes in short term wait count so that the load on the disks is accounted for. The load on the disks is often the most important factor. Use vmstat if you need the CPU load. Use iostat for the disk load. Use the load average to get both. (No, this is not a new thing in FreeBSD, this is how it works in all the operating systems that are based on BSD) To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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