On Fri, Apr 13, 2018 at 06:57:39PM -0700, Francisco Jerez wrote: > Peter Zijlstra <peterz@xxxxxxxxxxxxx> writes: > > > On Thu, Apr 12, 2018 at 12:55:39PM -0700, Francisco Jerez wrote: > >> Actually assuming that a single geometric feature of the power curve is > >> known -- it being convex in the frequency range allowed by the policy > >> (which is almost always the case, not only for Intel CPUs), the optimal > >> frequency for an IO-bound workload is fully independent of the exact > >> power curve -- It's just the minimum CPU frequency that's able to keep > >> the bottlenecking IO device at 100% utilization. > > > > I think that is difficult to determine with the information at hand. We > > have lost all device information by the time we reach the scheduler. > > I assume you mean it's difficult to tell whether the workload is > CPU-bound or IO-bound? Yeah, it's non-trivial to determine whether the > system is bottlenecking on IO, it requires additional infrastructure to > keep track of IO utilization (that's the purpose of PATCH 1), and even Note that I've not actually seen any of your patches; I got Cc'ed on later. _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
