Re: [PATCH 04/11] sched,x86: Enable Turbo Boost Max Technology

[Ingo Molnar]

* Tim Chen <tim.c.chen@xxxxxxxxxxxxxxx> wrote:

> Ingo,
> 
> This feature will be a clear benefit for client machines and
> less clear on servers.
> 
> This feature is most beneficial to single threaded workload running on
> a single socket that operates in mostly Turbo mode.  Client platform
> like Broadwell High End Desktop is the first one that supports it.
> Enablng this feature for such platform by default will be a win as it
> runs single threaded workload much of the time (10%-15% peformance
> upside).
> 
> On the other hand, a heavily loaded server that rarely operates in Turbo
> mode will benefit much less from this feature.  There is some overhead
> incurred by migrating load to the favored cores.  Some server folks
> have asked us to be cautious here and not to turn on ITMT scheduling
> by default.   Even so, when the server is lightly loaded, this feature
> can still be a win.  That said, this is future looking as we don't have
> any server with this feature today.
> 
> So if we take the approach to enable this feature by default for only
> single node system (using that as a criteria for client), will that seem
> reasonable to you?

I suppose that would work. Peter, any objections to such an approach?

Thanks,

	Ingo