Re: High priority tasks break SMP balancer?

[Christoph Lameter]

On Thu, 15 Nov 2007, Micah Dowty wrote:

> On all kernels I've tested from after your patch was committed, I can
> reproduce a problem where a single high-priority thread which wakes up
> very frequently can artificially inflate the SMP balancer's load
> average for one CPU, causing other tasks to be migrated off that
> CPU. The result is that this high-priority thread (which may only use
> a few percent CPU) gets an entire CPU to itself. Even if there are
> several busy-looping threads running, this CPU will be mostly idle.

I am a bit at a loss as to how this could relate to the patch. This looks 
like a load balance logic issue that causes the load calculation to go 
wrong?


-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/