SCHED_ULE should not be the default
tevans.uk at googlemail.com
Thu Dec 15 09:44:25 UTC 2011
On Thu, Dec 15, 2011 at 12:42 AM, Jeremy Chadwick
<freebsd at jdc.parodius.com> wrote:
> On Thu, Dec 15, 2011 at 12:39:50AM +0100, O. Hartmann wrote:
>> On 12/14/11 18:54, Tom Evans wrote:
>> > I believe the correct thing to do is to put some extra documentation
>> > into the handbook about scheduler choice, noting the potential issues
>> > with loading NCPU+1 CPU bound processes. Perhaps making it easier to
>> > switch scheduler would also help?
> Replying to Tom's comment here:
> It is already easy to switch schedulers. You change the option in your
> kernel config, rebuild kernel (world isn't necessary as long as you
> haven't csup'd between your last rebuild and now), make installkernel,
> shutdown -r now, done.
Your definition of 'easy' differs wildly from mine. How is that in any
way 'easy' to do across 200 servers?
> If what you're proposing is to make the scheduler changeable in
> real-time? I think that would require a **lot** of work for something
> that very few people would benefit from (please stop for a moment and
> think about the majority of the userbase, not just niche environments; I
> say this politely, not with any condescension BTW). Sure, it'd be
> "nice to have", but should be extremely low on the priority list (IMO).
Real time scheduler changing would be insane! I was thinking that
both/any/all schedulers could be compiled into the kernel, and the
choice of which one to use becomes a boot time configuration. You
don't have to recompile the kernel to change timecounter.
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