[haiku-development] Re: Thread migration strategy
- From: "Axel Dörfler" <axeld@xxxxxxxxxxxxxxxx>
- To: haiku-development@xxxxxxxxxxxxx
- Date: Thu, 26 Mar 2009 22:52:27 +0100 CET
André Braga <meianoite@xxxxxxxxx> wrote:
> Then the load-balancer migrates this thread to the best destination
> core among the candidates. Let W be the quantity of cores considered
> for receiving migrated threads, so that K <= W <= 2K. This is so that
> the algorithm scales reasonably well for a large number of cores.
Not sure this hog array will work so well - even lots of non-hogs hurt
latency which might be worse depending on what you want to achieve. A
load is balanced when each CPU has a similar thread profile (ie. the
ratio between interactive and computing threads), even though this
might not be the best solution if throughput is your worry.
> In order to avoid the ping-pong effect, a just-migrated thread could
> have a "cool-down" period where it would not be allowed to get to the
> "hogs" list.
If there would be a ping-pong effect, I guess the load balancer
wouldn't do a good job :-)
Bye,
Axel.
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