Hello,
I am profiling memory usage using utils::Rprof() and subsequently summarizing
the profile using utils::summaryRprof(). According to the documentation
?summaryRprof, the option `memory = "both"` reports "memory consumption in Mb
in addition to the timings", i.e. the unit is megabytes. However, looking at
the source code
(https://github.com/wch/r-source/blob/18652de8890d89563b923ff58b45ccb04d9955fe/src/library/utils/R/summRprof.R#L170)
suggests that memory is reported in mebibytes (division by 1048576 and not by
100000). This is in line with the following minimal example:
use_mb <- function(){a <- runif(1000000)}
use_mib <- function(){b <- runif(1024^2)}
Rprof("Rprof.out", memory.profiling=TRUE)
use_mb()
use_mib()
Rprof(NULL)
summaryRprof("Rprof.out", memory="both")
Do not source this code, but execute it line by line. This example returns the
output:
$by.self
self.time self.pct total.time total.pct mem.total
"runif" 0.04 100 0.04 100 15.6
$by.total
total.time total.pct mem.total self.time self.pct
"runif" 0.04 100 15.6 0.04 100
"use_mb" 0.02 50 7.6 0.00 0
"use_mib" 0.02 50 8.0 0.00 0
$sample.interval
[1] 0.02
$sampling.time
[1] 0.04
The example was run under:
R version 4.4.0 (2024-04-24 ucrt)
Platform: x86_64-w64-mingw32/x64
Running under: Windows 11 x64 (build 22631)
If the unit were megabytes, I would expect mem.total to be 16.4, 8.0, and 8.4
-- but rather it is 15.6, 7.6, and 8.0. Do you agree that this behavior is
unexpected or did I overlook something? If yes, I will file a bug report and
suggest that the documentation is changed to "memory consumption in MiB in
addition to the timings".
Best regards,
Lukas D Sauer
Biometrician
Institute of Medical Biometry
Heidelberg University Hospital | Im Neuenheimer Feld 130.3 | D-69120 Heidelberg
Tel. +49 6221 56-35036 | Fax. +49 6221 56-4195 | E-Mail:
sa...@imbi.uni-heidelberg.de
biometrie.uni-heidelberg.de | twitter.com/imbi_heidelberg
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