# How to check where memory is used in REPL?
**URL:** https://discourse.julialang.org/t/how-to-check-where-memory-is-used-in-repl/94895
**Category:** General Usage
**Created:** [February 20, 2023, 3:37am UTC](https://discourse.julialang.org/t/how-to-check-where-memory-is-used-in-repl/94895 "2023-02-20T03:37:04Z")
**Posts on this page:** 5
**Page:** 1
### Author:  [@jsjie](https://discourse.julialang.org/u/jsjie)
#### Post date: [February 20, 2023, 3:37am UTC](https://discourse.julialang.org/t/how-to-check-where-memory-is-used-in-repl/94895/1 "2023-02-20T03:37:04Z")
My package suffers from large memory usage, and I wanna know why by testing in REPL.
I track the total message in two ways:
1. examing result of `top`
2. use the following code in REPL:
`my_command = pipeline(`cat /proc/$(getpid())/statm`, `awk '{print $2}'`)`
` run(my_command)`
both ways give me similar results of about 3G.
Then I wanna know how these memory are used:
```julia
julia> varinfo()
name size summary
–––––––––––––––– ––––––––––– ––––––––––––––––––––––––––––––––––
Base Module
Core Module
InteractiveUtils 261.479 KiB Module
Main Module
ans 1.407 KiB Markdown.MD
c 1.263 GiB ***(something produced by my package)
err 8 bytes Int64
my_command 266 bytes Base.OrCmds
```
which only covers less than half of the total memory used. How can I find where other memory are used?
I also tried:
```julia
julia> varinfo(Revise)
name size summary
––––––––––––– ––––––––– ––––––––––––––––––––––––––––––––––––––––––
MethodSummary 216 bytes DataType
Revise 2.726 MiB Module
entr 0 bytes entr (generic function with 2 methods)
includet 0 bytes includet (generic function with 2 methods)
revise 0 bytes revise (generic function with 3 methods)
```
and
```julia
julia> varinfo(MyPackage)
name size summary
––––––– –––––––––– –––––––
MyPackage 15.182 MiB Module
```
Which seems to be little.
* * *
Strangely, after I go for lunch and return after 30min, the memory usage of the process is now 3.6G. No idea what happened.
* * *
It seems to be related be compiled methods, which uses far more memory than I’ve expect. But I don’t know how to get more details.
What I’ve done:
use top to track the memory usage of julia (1.7.1).
after starting a new process: ~200M
after using MyPackage: ~350M
after executing some precompile commands (~250 precompile commands, many third parties library are used): ~780M
after GC: ~720M
some output at this time:
```julia
julia> varinfo()
name size summary
–––––––––––––––– ––––––––––– –––––––
Base Module
Core Module
InteractiveUtils 253.909 KiB Module
Main Module
ans 1 byte Bool
julia> Base.gc_live_bytes()
383446566
```
For solving a real problem, many more methods will be compiled, so in the original problem, maybe more memory are used by compiled codes, but I’ve not find a way to figure out a precise number.
And, after all, it is strange that compiled code should use so many memory. Considering my package is expected to be used with mpi on a cluster with less than 4GB memory per core, this is too high a cost.
---
### Author:  [@aramirezreyes](https://discourse.julialang.org/u/aramirezreyes)
#### Post date: [February 20, 2023, 3:50am UTC](https://discourse.julialang.org/t/how-to-check-where-memory-is-used-in-repl/94895/2 "2023-02-20T03:50:04Z")
It could be that the memory is not taken by any variables but was used by variables that went out of scope. The garbage collector is supposed to recover them eventually but you can force it to act by doing:
```julia
GC.gc()
```
In the REPL and then checking again your memory usage.
---
### Author:  [@jsjie](https://discourse.julialang.org/u/jsjie)
#### Post date: [February 20, 2023, 4:12am UTC](https://discourse.julialang.org/t/how-to-check-where-memory-is-used-in-repl/94895/3 "2023-02-20T04:12:51Z")
The data reported above is after I run `GC.gc()`. It only frees about 80M memory.
---
### Author:  [@jakobnissen](https://discourse.julialang.org/u/jakobnissen)
#### Post date: [February 20, 2023, 8:04am UTC](https://discourse.julialang.org/t/how-to-check-where-memory-is-used-in-repl/94895/4 "2023-02-20T08:04:02Z")
You can try to look at `Base.summarysize` which tries to give the total size of all objects reachable from a given object. Try running it on all the objects inside `varinfo()`:
```julia
julia> x = rand(Float32, 1000, 1000);
julia> s = Dict(i => join(rand('A':'z', 200)) for i in 1:100);
julia> for name in names(Main)
thing = getproperty(Main, name)
thing isa Module && continue
println(String(name), ' ', Base.summarysize(thing))
end
ans 25336
s 25336
x 4000040
```
There are probably some edge cases I’ve forgotten about. For example, in my case above, `ans` and `s` are the same object, but appears twice in the output.
---
### Author:  [@jsjie](https://discourse.julialang.org/u/jsjie)
#### Post date: [February 21, 2023, 1:14am UTC](https://discourse.julialang.org/t/how-to-check-where-memory-is-used-in-repl/94895/5 "2023-02-21T01:14:16Z")
For the main object mentioned above, `Base.summarysize` also returns about 1.3G.