Re: Runnable threads on run queue

[Robert Hancock <hancockr@shaw.ca>]

Ask List wrote:
> Have an issue maybe someone on this list can help with. 
>
> At times of very high load the number of processes on the run queue drops to
>  0 then jumps really high and then drops to 0 and back and forth. It seems to
> last 10 seconds or so. If you look at this vmstat you can see an example of 
> what I mean. Now im not a linux kernel expert but i am thinking it has 
> something to do with the scheduling algorithm and locking of the run queue. 
> For this particular application I need all available threads to be processed as
> fast as possible. Is there a way for me to elimnate this behavior or at least
> minimize the window in which there are no threads on the run queue? Is there a
> sysctl parameter I can use?
>
> Please help.

This seems like a userspace issue to me. There is no way the scheduler 
would let the system sit idle for 10 seconds with runnable processes. I 
think Rik van Riel's comment about sendmail reacting to increased load 
average may be related to what's going on here.

--
Robert Hancock      Saskatoon, SK, Canada
To email, remove "nospam" from hancockr@nospamshaw.ca
Home Page: http://www.roberthancock.com/

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