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Performance regression in findall on Bool array with predicate #42187

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KristofferC opened this issue Sep 9, 2021 · 0 comments · Fixed by #42202
Closed

Performance regression in findall on Bool array with predicate #42187

KristofferC opened this issue Sep 9, 2021 · 0 comments · Fixed by #42202
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performance Must go faster regression Regression in behavior compared to a previous version

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@KristofferC
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Repro:

using BenchmarkTools
const y = rand(Bool, 1000)
@btime findall(x -> x > 1, y)

1.6:

julia> @btime findall(x -> x > 1, y)
  300.167 ns (1 allocation: 80 bytes)
Int64[]

1.7:

julia> @btime findall(x -> x > 1, y)
  702.505 ns (6 allocations: 4.50 KiB)
Int64[]

Also, note the increase in allocations
@KristofferC KristofferC added performance Must go faster regression Regression in behavior compared to a previous version labels Sep 9, 2021
jakobnissen added a commit to jakobnissen/julia that referenced this issue Sep 10, 2021
@jakobnissen
Optimize findall(f, ::AbstractArray{Bool})
bd6517d 
* Take shortcuts if f(::Bool) always returns true or false
* Avoid branching in main loop to please branch predictor
* Switch to indexing-agnostic code
* Fix regression mentioned in JuliaLang#42187
jakobnissen added a commit to jakobnissen/julia that referenced this issue Sep 10, 2021
@jakobnissen
Optimize findall(f, ::AbstractArray{Bool})
ec15068 
* Take shortcuts if f(::Bool) always returns true or false
* Avoid branching in main loop to please branch predictor
* Switch to indexing-agnostic code
* Fix regression mentioned in JuliaLang#42187
@jakobnissen jakobnissen mentioned this issue Sep 10, 2021
Merged
jakobnissen added a commit to jakobnissen/julia that referenced this issue Sep 12, 2021
@jakobnissen
Optimize findall(f, ::AbstractArray{Bool})
8340cc9 
* Take shortcuts if f(::Bool) always returns true or false
* Avoid branching in main loop to please branch predictor
* Switch to indexing-agnostic code
* Fix regression mentioned in JuliaLang#42187
jakobnissen added a commit to jakobnissen/julia that referenced this issue Sep 12, 2021
@jakobnissen
Optimize findall(f, ::AbstractArray{Bool})
2aa6627 
* Take shortcuts if f(::Bool) always returns true or false
* Avoid branching in main loop to please branch predictor
* Switch to indexing-agnostic code
* Fix regression mentioned in JuliaLang#42187
jakobnissen added a commit to jakobnissen/julia that referenced this issue Nov 27, 2021
@jakobnissen
Optimize findall(f, ::AbstractArray{Bool})
d315c66 
* Take shortcuts if f(::Bool) always returns true or false
* Avoid branching in main loop to please branch predictor
* Switch to indexing-agnostic code
* Fix regression mentioned in JuliaLang#42187
jakobnissen added a commit to jakobnissen/julia that referenced this issue Dec 26, 2021
@jakobnissen
Optimize findall(f, ::AbstractArray{Bool})
1678a1a 
* Take shortcuts if f(::Bool) always returns true or false
* Avoid branching in main loop to please branch predictor
* Switch to indexing-agnostic code
* Fix regression mentioned in JuliaLang#42187
@vtjnash vtjnash mentioned this issue Feb 13, 2022
Closed
@LilithHafner LilithHafner mentioned this issue Aug 20, 2022
Closed
@jakobnissen jakobnissen mentioned this issue May 16, 2023
Draft
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Optimize findall(f, ::AbstractArray{Bool}) jakobnissen/julia
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@KristofferC