# Allocations (again...)
**URL:** https://discourse.julialang.org/t/allocations-again/90780
**Category:** Performance
**Tags:** question, allocations
**Created:** [November 24, 2022, 8:58pm UTC](https://discourse.julialang.org/t/allocations-again/90780 "2022-11-24T20:58:35Z")
**Posts on this page:** 16
**Page:** 1
### Author:  [@aaraujo71](https://discourse.julialang.org/u/aaraujo71)
#### Post date: [November 24, 2022, 8:58pm UTC](https://discourse.julialang.org/t/allocations-again/90780/1 "2022-11-24T20:58:35Z")
When I run
```julia
using BenchmarkTools
function test(x, Y)
sum!(x, Y')
return nothing
end
x = rand(Float64, 100)
Y = rand(Float64, 1, 100)
@btime(test(x, Y))
```
I get the following:
```julia
367.952 ns (2 allocations: 96 bytes)
```
I don’t think I should get any allocations. Can someone please explain what’s going on? And how can I avoid such allocations? (In my real application I have to do a similar computation millions of times.)
Thank you in advance.
---
### Author:  [@rveltz](https://discourse.julialang.org/u/rveltz)
#### Post date: [November 24, 2022, 9:05pm UTC](https://discourse.julialang.org/t/allocations-again/90780/2 "2022-11-24T21:05:52Z")
that’s quite nothing
```julia
julia> @btime test($x,$Y);
372.976 ns (2 allocations: 96 bytes)
```
---
### Author:  [@gustaphe](https://discourse.julialang.org/u/gustaphe)
#### Post date: [November 24, 2022, 9:14pm UTC](https://discourse.julialang.org/t/allocations-again/90780/3 "2022-11-24T21:14:56Z")
Where and how is `test()` defined? We would need to know to tell where the allocations are coming from.
---
### Author:  [@aaraujo71](https://discourse.julialang.org/u/aaraujo71)
#### Post date: [November 24, 2022, 9:16pm UTC](https://discourse.julialang.org/t/allocations-again/90780/4 "2022-11-24T21:16:21Z")
The code I have shown was fully typed on a .jl file
---
### Author:  [@aaraujo71](https://discourse.julialang.org/u/aaraujo71)
#### Post date: [November 24, 2022, 9:18pm UTC](https://discourse.julialang.org/t/allocations-again/90780/5 "2022-11-24T21:18:03Z")
It’s a lot if you cycle it through tens of thousands of times
---
### Author:  [@gustaphe](https://discourse.julialang.org/u/gustaphe)
#### Post date: [November 24, 2022, 9:20pm UTC](https://discourse.julialang.org/t/allocations-again/90780/6 "2022-11-24T21:20:50Z")
If you restart Julia and run that code you’ll see it error out. In the shown snippet you only define a two argument method, and then run one with zero arguments. Possibly you’ve defined that one before, and it contains something that allocates.
---
### Author:  [@aaraujo71](https://discourse.julialang.org/u/aaraujo71)
#### Post date: [November 24, 2022, 9:23pm UTC](https://discourse.julialang.org/t/allocations-again/90780/7 "2022-11-24T21:23:21Z")
Sorry, I’ve pasted the wrong code. I’ll update it.
---
### Author:  [@aaraujo71](https://discourse.julialang.org/u/aaraujo71)
#### Post date: [November 24, 2022, 9:25pm UTC](https://discourse.julialang.org/t/allocations-again/90780/8 "2022-11-24T21:25:13Z")
I have updated it and I still get 2 allocations
---
### Author:  [@lmiq](https://discourse.julialang.org/u/lmiq)
#### Post date: [November 24, 2022, 11:44pm UTC](https://discourse.julialang.org/t/allocations-again/90780/9 "2022-11-24T23:44:02Z")
I think that `Y'` allocates (write a loop instead, for example).
---
### Author:  [@DNF](https://discourse.julialang.org/u/DNF)
#### Post date: [November 25, 2022, 8:08am UTC](https://discourse.julialang.org/t/allocations-again/90780/10 "2022-11-25T08:08:14Z")
What? When did that start? Adjoints have never allocated as far as I know.
Anyway:
```julia
julia> @btime test($x, $Y)
124.499 ns (0 allocations: 0 bytes)
```
No allocations here, @aaraujo71
---
### Author:  [@pablosanjose](https://discourse.julialang.org/u/pablosanjose)
#### Post date: [November 25, 2022, 8:26am UTC](https://discourse.julialang.org/t/allocations-again/90780/11 "2022-11-25T08:26:44Z")
> [@aaraujo71](#):
>
> ```julia
> using BenchmarkTools
>
> function test(x, Y)
> sum!(x, Y')
> return nothing
> end
>
> x = rand(Float64, 100)
> Y = rand(Float64, 1, 100)
> @btime(test(x, Y))
>
> ```
I do see the reported allocations in v1.8.2 under macos (arm)
```julia
julia> @btime(test($x, $Y))
358.333 ns (2 allocations: 96 bytes)
```
EDIT: the issue is the adjoint. Without it, we’re back to zero allocations. I think it is indeed a bug.
EDIT2: no allocations on v1.8.1 on linux! 2 allocations in macos v1.9.0.alpha1
---
### Author:  [@DNF](https://discourse.julialang.org/u/DNF)
#### Post date: [November 25, 2022, 8:32am UTC](https://discourse.julialang.org/t/allocations-again/90780/12 "2022-11-25T08:32:12Z")
> [@pablosanjose](#):
>
> EDIT: the issue is the adjoint. Without it, we’re back to zero allocations. I think it is indeed a bug.
> EDIT2: no allocations on v1.8.1 on linux! 2 allocations in macos v1.9.0.alpha1
Zero allocations on 1.8.0 on Windows, that is _with_ the adjoint.
---
### Author:  [@pablosanjose](https://discourse.julialang.org/u/pablosanjose)
#### Post date: [November 25, 2022, 8:38am UTC](https://discourse.julialang.org/t/allocations-again/90780/13 "2022-11-25T08:38:50Z")
And again 2 allocation in 1.8.3 under linux. It seems there is a regression that was introduced in 1.8.2 or 1.8.3
---
### Author:  [@pablosanjose](https://discourse.julialang.org/u/pablosanjose)
#### Post date: [November 25, 2022, 8:44am UTC](https://discourse.julialang.org/t/allocations-again/90780/14 "2022-11-25T08:44:58Z")
Opened an issue
>
>
> Ref: https://discourse.julialang.org/t/allocations-again/90780/13
>
> António Ara…újo noted the following, which started happening sometime between v1.8.1 and v1.8.3
>
> \`\`\`julia
> using BenchmarkTools
>
> function test(x, Y)
> sum!(x, Y')
> return nothing
> end
>
> x = rand(Float64, 100)
> Y = rand(Float64, 1, 100)
> \`\`\`
> \`\`\`julia
> julia\> @btime(test($x, $Y))
> 301.619 ns (2 allocations: 96 bytes)
> \`\`\`
> In v1.8.0 and v1.8.1 we have instead
> \`\`\`julia
> julia\> @btime(test($x, $Y))
> 68.719 ns (0 allocations: 0 bytes)
> \`\`\`
---
### Author:  [@aaraujo71](https://discourse.julialang.org/u/aaraujo71)
#### Post date: [November 25, 2022, 12:28pm UTC](https://discourse.julialang.org/t/allocations-again/90780/15 "2022-11-25T12:28:13Z")
Thank you all. I am reprogramming may whole functions using loops.
---
### Author:  [@DNF](https://discourse.julialang.org/u/DNF)
#### Post date: [November 25, 2022, 2:26pm UTC](https://discourse.julialang.org/t/allocations-again/90780/16 "2022-11-25T14:26:34Z")
It shouldn’t really be necessary. I mean, loops are fine, but it’s too bad to have to use them over clean simple function calls like `sum!`. This here seems like a spurious allocation, which will possibly be fixed in a patch release in not too long.