On Thu, Sep 05, 2019 at 12:13:47PM +0100, Qais Yousef wrote: > On 09/05/19 12:46, Peter Zijlstra wrote:
> > This is important because we want to be able to bias towards less > > importance to (tail) latency as well as more importantance to (tail) > > latency. > > > > Specifically, Oracle wants to sacrifice (some) latency for throughput. > > Facebook OTOH seems to want to sacrifice (some) throughput for latency. > > Another use case I'm considering is using latency-nice to prefer an idle CPU > if > latency-nice is set otherwise go for the most energy efficient CPU. > > Ie: sacrifice (some) energy for latency. > > The way I see interpreting latency-nice here as a binary switch. But > maybe we can use the range to select what (some) energy to sacrifice > mean here. Hmmm. It cannot be binary, per definition is must be ternary, that is, <0, ==0 and >0 (or middle value if you're of that persuasion). In your case, I'm thinking you mean >0, we want to lower the latency. Anyway; there were a number of things mentioned at OSPM that we could tie into this thing and finding sensible mappings is going to be a bit of trial and error I suppose. But as patrick said; we're very much exporting a BIAS knob, not a set of behaviours.
