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Understanding Sysload values

Posted: October 13th, 2012, 2:29 pm
by dynamis_dk
I just want to get a little clarification on the sysload values. As I understand from a quick search its a break down of loads over 3 time periods (1,5 & 15min?). I've seen a post which suggests you multiply by 100 to give is as a percentage value but that doesn't work as i often have the values at 1.x or 2.x etc

Can someone fill me in on what the values represent? Ideally I'd like to adjust it so its shows as a current CPU use percentage value... from what I can tell the misc.py holds something to do with the calculations.

Re: Understanding Sysload values

Posted: October 13th, 2012, 4:57 pm
by sander
"man uptime" says:
System load averages is the average number of processes that are either in a runnable or uninterruptable state. A process in a
runnable state is either using the CPU or waiting to use the CPU. A process in uninterruptable state is waiting for some I/O access,
eg waiting for disk. The averages are taken over the three time intervals. Load averages are not normalized for the number of CPUs
in a system, so a load average of 1 means a single CPU system is loaded all the time while on a 4 CPU system it means it was idle
75% of the time.
My rule of thumb:
sysload below 1.00 is good.
Sysload above 1.00 is bad.
Sysload above 5 is really bad; your system will annoyingly unresponsive in interactive sessions.

Note: A high sysload is bearable if the system just working in the background and not used for interaction

Re: Understanding Sysload values

Posted: October 13th, 2012, 7:10 pm
by dynamis_dk
So I'm I right in thinking a solid '2' would mean a dual core CPU is fully utilised? or i could have up to a value of '4' for a Dual Core (with Hyperthreading) cpu?

Is that taking into consideration your 'rule of thumb' is based on a single core cpu?

Afraid I come very much from a windows world lol.

My main wonder was how hard the system is working when extracting and running PAR2 as I would like to have as many aspect of the system multicore capable as its running a i3-2120. Its a 0% interaction box for the most part as its a unraid server with Sabnzbd etc running on a spare drive.

Re: Understanding Sysload values

Posted: October 14th, 2012, 12:44 am
by sander
dynamis_dk wrote:So I'm I right in thinking a solid '2' would mean a dual core CPU is fully utilised? or i could have up to a value of '4' for a Dual Core (with Hyperthreading) cpu?

Is that taking into consideration your 'rule of thumb' is based on a single core cpu?
I would think so ... however, my laptop, with a i3 dual core + HT (thus four cores), is not usable at sysload 4. So I'm not so sure if HT counts.