> -----Original Message-----
> From: Adam Nellemann [mailto:adam at nellemann dot nu]
> Sent: Thursday, 8 April 2004 11:45 AM
> To: rick at scorpion dot co dot th; m0n0wall at lists dot m0n0 dot ch
> Subject: Re: [m0n0wall] about the load averages: 2.11, 0.07, 0.05
> Hi Rick,
> Rick Ruggiero wrote:
> > It means, the following:
> > load averages: 2.11% (Avg. process queue last minute), 0.07% (Avg.
> > process queue last 5 minutes), 0.05% (avg process queue last 15
> > minutes).
> > I don't have the m0n0wall running properly yet, but generally
> > uptime is the same on all UNIX platforms.
> I think it was previously established that the three numbers
> corrospond to the average percentage for the last 1, 5 and 15
> minutes respectivly, but I do find it somewhat illuminating
> that these numbers are related to the process queue.
> However, there still remain some things to be explained:
> - How to understand the term "process queue" precisely (this
> might be simple stuff for a *NIX guru, whereas I, not knowing
> much about *NIX, can only guess at the exact meaning).
The load average numbers give the number of jobs in the run queue
(actively being processed)
> - What the number (percentage) indicates, the average
> wait-time in the queue, the average queue length or something
> else entirely?
No, unfortunately you cannot use this number to predict CPU,IO latency,
etc. Each process has a discrete impact many other system metrics which
does affect overall system performance (and the values being displayed).
> - What is this percentage relative to? (That is, what is
> 100.00%, and can it become higher than that?)
Yes, it is relative to 100%; and no, it does not display greater than
100% (well from my experience at least).
> - And finally, how this "average process queue" percentage
> relates to such things as CPU load, latency and general
> system performance?
This is all dependant on the processes currently in the run queue. Some
processes may be blocked on I/O which often has a severe impact on this
value. However, generally speaking (and I am opening myself to abuse
here) any time your process average for 1-5 minutes is over 6, you will
find that process spawning is dramatically affected.
I do not have a magic answer on this, or a formula where you can start
doing transaction prediction modelling.
> Unless one has some idea of the answers to the above
> questions, the numbers have little meaning and will be of
> even less use. If, on the other hand, you know how these
> numbers are arrived at, you could use them, among many
> things, to see if it is time to start looking for faster
> hardware. Also, we might perhaps finally get some
> authoritative statements about how much bandwidth m0n0wall
> can handle on particular platforms (such as the Soekris boards).
I think if you look at my statement above, you may have a glimpse as to
my approach to this question; If my CPU is regularly demonstrating a
process queue of 6 or greater, I would look seriously into a processor
upgrade, however if my load averages were "load averages: 2.11, 0.07,
0.05", I'd be very happy.
I hope I was a little clearer with this response.