Assess performance of elements within an R function

I know it is possible to estimate the time it takes to complete a function (e.g., with sys.time(), but is there a way to benchmark a function and see which element within the function takes the longest/shortest?

So for example, given the code below, I should be able to performance test the function and determine for run 1, function_long is a bottleneck but for run 2, function_custom is the issue.

function_short <- function(){
  Sys.sleep(2)
}

function_long <- function(){
  sys.sleep(8)
}

function_custom <- function(x){
  sys.sleep(x)
}

function_to_test <- function(x){
  print("Starting function")
  
  print("2 second rest..")
  function_short()
  
  print("8 second rest..")
  function_long()
  
  print(paste0(x), " second rest..")
  function_custom(x)
}

# test these
## run 1
function_to_test(1)

## run 2
function_to_test(10)

Edit: There are a few different options. You could use the built in profiler like this

  function_short <- function(){
    Sys.sleep(2)
  }
  
  function_long <- function(){
    Sys.sleep(8)
  }
  
  function_custom <- function(x){
    Sys.sleep(x)
  }
  
  
function_custom <- function(x){
  Sys.sleep(x)
}

function_to_test <- function(x){
  print("Starting function")
  
  print("2 second rest..")
  function_short()
  
  print("8 second rest..")
  function_long()
  
  print(paste0(x), " second rest..")
  function_custom(x)
} 


Rprof('my_fun')

function_to_test(2)
#> [1] "Starting function"
#> [1] "2 second rest.."
#> [1] "8 second rest.."
#> Warning in print.default(paste0(x), " second rest.."): NAs introduced by
#> coercion
#> Error in print.default(paste0(x), " second rest.."): invalid printing digits -2147483648

Rprof(NULL)

^{Created on 2024-08-16 with reprex v2.1.1}

and in the terminal run 'R CMD Rprof my_fun which catch some of the bottle necks. Alternatively you could do

script = 'function_short <- function(){
  Sys.sleep(2)
}

function_long <- function(){
  Sys.sleep(8)
}

function_custom <- function(x){
  Sys.sleep(x)
}


function_custom <- function(x){
  Sys.sleep(x)
}

function_to_test <- function(x){
  print("Starting function")
  
  print("2 second rest..")
  function_short()
  
  print("8 second rest..")
  function_long()
  
  print(paste0(x), " second rest..")
  function_custom(x)
} '

writeLines(script, con = "script.R")

source('script.R')

profvis::profvis(function_to_test(2))

Which will open an interactive view of the run time for each parts of the function.

^{Created on 2024-08-16 with reprex v2.1.1}