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Subject: Re: ULE on ARM
From: Ian Lepore <ian@FreeBSD.org>
To: Ruslan Bukin <br@FreeBSD.org>
In-Reply-To: <20140307141406.GA79223@machdep.com>
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Date: Fri, 07 Mar 2014 07:25:04 -0700
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On Fri, 2014-03-07 at 18:14 +0400, Ruslan Bukin wrote:
> I discovered just a couple of ARM kernel configs
> uses SCHED_ULE, but all other uses SCHED_4BSD
> 
> any disadvantages to use ULE scheduler on ARM?
> or it is just because of historical reasons?
> 
> I enabled ULE on Freescale Vybrid and running
> it for a long time just fine.
> 
> according to my subjective impressions ULE
> works better on ARM in sound applications
> 
> -Ruslan

The widespread advice from a few years ago was that ULE was better for
SMP and 4BSD was better for UP.  I don't know whether that's still true
(or whether it was ever true).  I do know that there are fewer responses
on mailing lists of "try switching the scheduler to 4BSD" as a way of
fixing problems these days.  I switched imx6 to ULE when adding SMP
support for it.

-- Ian