Unusually high LA without any load at FreeBSD9-BETA2

[Alex Kozlov]

On Tue, Sep 06, 2011 at 05:22:02PM +0000, Poul-Henning Kamp wrote:
> In message <4E66547D.2030907 at cran.org.uk>, Bruce Cran writes:
>>On 06/09/2011 18:05, Garrett Cooper wrote:
>>> What is "LA"?
>>Load Average?
> We should kille the load avarage as a measure for system activity,
> it only has any relevance if you run heavy CPU bound processes.
It may be true, but in current kernel from beginning of june I would
see la about 0,01 in this situation.

Note that cpu idling:
dev.cpu.0.freq: 300
dev.cpu.0.freq_levels: 2200/35000 1925/30625 1650/26250 1600/23000 1400/20125 1200/15000 1050/13125 900/11250 750/9375 600/7500 450/5625 300/3750 150/1875
dev.cpu.0.cx_supported: C1/1 C2/1 C3/17
[...]
11 root        2 155 ki31     0K    32K CPU1    1  29.4H 200.00% idle

I think process accounting get broken or something like this.


> If the majority of your threads yield their quantum, load average
> contains absolutely no information of any relevance to system
> capacity.
>
> Try this:
>
> 	main()
> 		for (i = 0; i < 10000; i++)
> 			start thread {
> 				calculate time until top of next second
> 				sleep (until then)
> 			}
>
> You'll see a monster load-avg on idle cpus.


--
Adios