I've found the main problem. I have a function which repeatedly accesses a 6-dimensional array in a loop. This function took no time in 0.4, but is actually very slow in 0.5. My problem looks very similar to 18774 <https://github.com/JuliaLang/julia/issues/18774>. Here's an example:

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A3 = rand(10, 10, 10); function test3(A, nx1, nx2, nx3) for i = 1:10_000_000 A[nx1, nx2, nx3] end end A5 = rand(10, 10, 10, 10, 10); function test5(A, nx1, nx2, nx3, nx4, nx5) for i = 1:10_000_000 A[nx1, nx2, nx3, nx4, nx5] end end A6 = rand(10, 10, 10, 10, 10, 10); function test6(A, nx1, nx2, nx3, nx4, nx5, nx6) for i = 1:10_000_000 A[nx1, nx2, nx3, nx4, nx5, nx6] end end function test6_fast(A, nx1, nx2, nx3, nx4, nx5, nx6) Asize = size(A) for i = 1:10_000_000 A[sub2ind(Asize, nx1, nx2, nx3, nx4, nx5, nx6 )] end end @time test3(A3, 1, 1, 1) @time test5(A5, 1, 1, 1, 1, 1) @time test6(A6, 1, 1, 1, 1, 1, 1) @time test6_fast(A6, 1, 1, 1, 1, 1, 1) test6 takes 0.01s in 0.4 and takes 15s in 0.5. Using a linear index fixes the problem. On Friday, September 30, 2016 at 2:30:02 AM UTC-4, Mauro wrote: > > On Fri, 2016-09-30 at 03:45, Andrew <owe...@gmail.com <javascript:>> > wrote: > > I checked, and my objective function is evaluated exactly as many times > > under 0.4 as it is under 0.5. The number of iterations must be the same. > > > > I also looked at the times more precisely. For one particular function > call > > in the code, I have: > > > > 0.4 with old code: 6.7s 18.5M allocations > > 0.4 with 0.5 style code(regular anonymous functions) 11.6s, 141M > > allocations > > 0.5: 36.2s, 189M allocations > > > > Surprisingly, 0.4 is still much faster even without the fast anonymous > > functions trick. It doesn't look like 0.5 is generating many more > > allocations than 0.4 on the same code, the time is just a lot slower. > > Sounds like your not far off a minimal, working example. Post it and > I'm sure it will be dissected in no time. (And an issue can be filed). > > > On Thursday, September 29, 2016 at 3:36:46 PM UTC-4, Tim Holy wrote: > >> > >> No real clue about what's happening, but my immediate thought was that > if > >> your algorithm is iterative and uses some kind of threshold to decide > >> convergence, then it seems possible that a change in the accuracy of > some > >> computation might lead to it getting "stuck" occasionally due to > roundoff > >> error. That's probably more likely to happen because of some kind of > >> worsening rather than some improvement, but either is conceivable. > >> > >> If that's even a possible explanation, I'd check for unusually-large > >> numbers of iterations and then print some kind of convergence info. > >> > >> Best, > >> --Tim > >> > >> On Thu, Sep 29, 2016 at 1:21 PM, Andrew <owe...@gmail.com > <javascript:>> > >> wrote: > >> > >>> In the 0.4 version the above times are pretty consistent. I never > observe > >>> any several thousand allocation calls. I wonder if compilation is > occurring > >>> repeatedly. > >>> > >>> This isn't terribly pressing for me since I'm not currently working on > >>> this project, but if there's an easy fix it would be useful for future > work. > >>> > >>> (sorry I didn't mean to post twice. For some reason hitting spacebar > was > >>> interpreted as the post command?) > >>> > >>> > >>> On Thursday, September 29, 2016 at 2:15:35 PM UTC-4, Andrew wrote: > >>>> > >>>> I've used @code_warntype everywhere I can think to and I've only > found > >>>> one Core.box. The @code_warntype looks like this > >>>> > >>>> Variables: > >>>> #self#::#innerloop#3133{#bellman_obj} > >>>> state::State{IdioState,AggState} > >>>> EVspline::Dierckx.Spline1D > >>>> model::Model{CRRA_Family,AggState} > >>>> policy::PolicyFunctions{Array{Float64,6},Array{Int64,6}} > >>>> OO::NW > >>>> > >>>> > #3130::##3130#3134{State{IdioState,AggState},Dierckx.Spline1D,Model{CRRA_Family,AggState},PolicyFunctions{Array{Float64,6},Array{Int64,6}},NW,#bellman_obj} > > > >>>> > >>>> Body: > >>>> begin > >>>> > >>>> > #3130::##3130#3134{State{IdioState,AggState},Dierckx.Spline1D,Model{CRRA_Family,AggState},PolicyFunctions{Array{Float64,6},Array{Int64,6}},NW,#bellman_obj} > > > >>>> = $(Expr(:new, > >>>> > ##3130#3134{State{IdioState,AggState},Dierckx.Spline1D,Model{CRRA_Family,AggState},PolicyFunctions{Array{Float64,6},Array{Int64,6}},NW,#bellman_obj}, > > > >>>> :(state), :(EVspline), :(model), :(policy), :(OO), > >>>> :((Core.getfield)(#self#,:bellman_obj)::#bellman_obj))) > >>>> SSAValue(0) = > >>>> > #3130::##3130#3134{State{IdioState,AggState},Dierckx.Spline1D,Model{CRRA_Family,AggState},PolicyFunctions{Array{Float64,6},Array{Int64,6}},NW,#bellman_obj} > > > >>>> > >>>> > (Core.setfield!)((Core.getfield)(#self#::#innerloop#3133{#bellman_obj},:obj)::CORE.BOX,:contents,SSAValue(0))::##3130#3134{State{IdioState,AggState},Dierckx.Spline1D,Model{CRRA_Family,AggState},PolicyFunctions{Array{Float64,6},Array{Int64,6}},NW,#bellman_obj} > > > >>>> return SSAValue(0) > >>>> > >>>> > end::##3130#3134{State{IdioState,AggState},Dierckx.Spline1D,Model{CRRA_Family,AggState},PolicyFunctions{Array{Float64,6},Array{Int64,6}},NW,#bellman_obj} > > > >>>> > >>>> > >>>> I put the CORE.BOX in all caps near the bottom. > >>>> > >>>> I have no idea if this is actually a problem. The return type is > stable. > >>>> Also, this function appears in an outer loop. > >>>> > >>>> What I noticed putting a @time in places is that in 0.5, occasionally > >>>> calls to my nonlinear equation solver take a really long time, like > here: > >>>> > >>>> 0.069224 seconds (9.62 k allocations: 487.873 KB) > >>>> 0.000007 seconds (39 allocations: 1.922 KB) > >>>> 0.000006 seconds (29 allocations: 1.391 KB) > >>>> 0.000011 seconds (74 allocations: 3.781 KB) > >>>> 0.000009 seconds (54 allocations: 2.719 KB) > >>>> 0.000008 seconds (54 allocations: 2.719 KB) > >>>> 0.000008 seconds (49 allocations: 2.453 KB) > >>>> 0.000007 seconds (44 allocations: 2.188 KB) > >>>> 0.000007 seconds (44 allocations: 2.188 KB) > >>>> 0.000006 seconds (39 allocations: 1.922 KB) > >>>> 0.000007 seconds (39 allocations: 1.922 KB) > >>>> 0.000006 seconds (39 allocations: 1.922 KB) > >>>> 0.000005 seconds (34 allocations: 1.656 KB) > >>>> 0.000005 seconds (34 allocations: 1.656 KB) > >>>> 0.000004 seconds (29 allocations: 1.391 KB) > >>>> 0.000004 seconds (24 allocations: 1.125 KB) > >>>> 0.007399 seconds (248 allocations: 15.453 KB) > >>>> 0.000009 seconds (30 allocations: 1.594 KB) > >>>> 0.000004 seconds (25 allocations: 1.328 KB) > >>>> 0.000004 seconds (25 allocations: 1.328 KB) > >>>> > >>>> 0.000010 seconds (70 allocations: 3.719 KB) > >>>> 0.072703 seconds (41.74 k allocations: 1.615 MB) > >>>> > >>>> > >>>> > >>>> > >>>> > >>>> > >>>> > >>>> > >>>> On Thursday, September 29, 2016 at 1:37:18 AM UTC-4, Kristoffer > Carlsson > >>>> wrote: > >>>>> > >>>>> Look for Core.Box in @code_warntype. See > >>>>> https://github.com/JuliaLang/julia/issues/15276 > >>>> > >>>> > >> >