whats going on with the scheduler?

Terry Lambert tlambert2 at mindspring.com
Tue Jul 8 03:55:43 PDT 2003

Andy Farkas wrote:
> On 7 Jul 2003, Lanny Baron wrote:
> > A load of 3 is pretty high. I think you have more going on.
> Not for my box. Its only running at 75% cpu power. Its got four
> processors, so a load of 4 is when its running flat out. And I also said
> that the box is idle other than the 3 setiathomes.
> What I'm trying to find out is why at load 3 when adding another semi-cpu
> intensive process, the load starts fluctuating between 2 and 3, when it
> should go to a steady 3.4 or something. So the load actually goes down
> when I run another process!

It's not clear what your link speed is, but it's possible that
what's happening is that the setiathome processes are stalling
waiting for work units because you are using up your available
network bandwidth.  This is usually the case when you have an
asymmetric link speed (e.g. cablemodem or DSL) and are trying
to push data through the small pipe: it's very easy to monopolize
all the buffers in the router at the other end of the link, such
that you don't end up getting ACK packets out to keep the data
pipe down full.

If this is what's ahppening, you might want to try bandwidth
limiting the scp and/or running with Alt-Q and/or begging Julian
for the code he wrote at Whistle, which beats the snot out of
Alt-Q...  8-).

-- Terry

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