Re: SCHED_ULE should not be the default

From: Bruce Cran <bruce_at_cran.org.uk>
Date: Mon, 12 Dec 2011 16:18:35 +0000
On 12/12/2011 15:51, Steve Kargl wrote:
> This comes up every 9 months or so, and must be approaching FAQ 
> status. In a HPC environment, I recommend 4BSD. Depending on the 
> workload, ULE can cause a severe increase in turn around time when 
> doing already long computations. If you have an MPI application, 
> simply launching greater than ncpu+1 jobs can show the problem. PS: 
> search the list archives for "kargl and ULE". 

This isn't something that can be fixed by tuning ULE? For example for 
desktop applications kern.sched.preempt_thresh should be set to 224 from 
its default. I'm wondering if the installer should ask people what the 
typical use will be, and tune the scheduler appropriately.

-- 
Bruce Cran
Received on Mon Dec 12 2011 - 15:18:39 UTC

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