[PATCH PR90240][RFC]Avoid scaling cost overflow by introducing scaling bound
Mon Apr 29 12:13:00 GMT 2019
On Sat, Apr 27, 2019 at 6:13 AM bin.cheng <firstname.lastname@example.org> wrote:
> This is the draft patch avoiding scaling cost overflow by introducing a scaling bound
> in IVOPTs. For now the bound is 20, and scaling factor will be further scaled wrto
> this bound. For example, scaling factor like 1, 1000, 2000(max) would be scaled to
> 1, 10, 20 correspondingly.
> HI Martin, I remember you introduced comp_cost/cost_scaling to improve one case
> in spec2017. Unfortunately I don't have access to the benchmark now, could you help
> verify that if this patch has performance issue on it please? Thanks
> Bootstrap and test on x86_64, and this is for further comment/discussion.
+ float factor = 1.0f * bfreq / lfreq;
+ if (adjust_factor_p)
+ factor *= COST_SCALING_FACTOR_BOUND;
+ factor = factor * lfreq / max_freq;
+ body[i]->aux = (void *)(intptr_t)(int) factor;
float computations on the host shouldn't be done.
I wonder if changing comp_cost::cost to int64_t would help instead? See also my
suggestion to use gmp.
Otherwise the approach looks sane to me - can we then even assert that
happen and thus INFTY only appears if we manually set such cost?
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