Windows Rgui.exe 4.2.0: Call of txtProgressBar() slows down dramatically after subsequent calls

On 5/19/22 22:34, Paulo Barata wrote:

There runs of Tobias' foo function on different versions of R that I 
have installed here.

R version 4.1.1 Patched (2021-09-30 r80997)
elapsed time of three trials: 1.31 / 1.33 / 1.35

R version 4.1.2 Patched (2021-11-02 r81131)
elapsed time of three trials: 1.34 / 1.34 / 1.34

R version 4.1.3 Patched (2022-03-10 r81878)
elapsed time of three trials: 1.33 / 1.34 / 1.37

R version 4.2.0 Patched (2022-05-17 r82371 ucrt)
elapsed time of three trials: 7.14 / 17.56 / 27.21

Platform is always: x86_64-w64-mingw32/x64 (64-bit)
RGui.exe running on Windows 10 Professional 64-bit (build 19044.1706)

Not only, as Tobias has shown, there is an increasing time among the 
three trials in R 4.2.0 Patched, but also the average time for each 
of the 4.1.X Patched versions (with nearly constant time each) is 
well smaller than the first trial with R 4.2.0 Patched.

Thanks, yes, I can reproduce the problem. Changing the implementation 
of the progress bar to print "\n" instead of "\r" makes the problem go 
away (and type=2 and 3 have the problem and use \r, while type=1 
doesn't have the problem nor uses \r). Perhaps the carriage return is 
not interpreted correctly and the line somehow internally keeps the 
previously printed characters, always adding the new ones at the end. 
That is also consistent with that the time is increasing linearly. I 
will investigate further.

Best
Tomas

Regards,

Paulo Barata

(Rio de Janeiro - Brazil)

----------------------------------------------------------

On 19/05/2022 15:37, Tobias Schoch wrote:

The issue appears in Rgui.exe version 4.2.0 (called "new" version; 
see bottom). The issue does NOT appear with Rterm.exe (same R version).

I provide a minimal example (foo) below. If I run function foo 3 
times in a row, the execution time increases considerably (although 
it should not).

1st foo call: 5 seconds
2nd foo call: 13 seconds
3rd foo call: 20 seconds

The execution time keeps increasing when I call foo more often. In 
addition, Rgui.exe becomes laggy in taking input from the keyboard.

Sometimes, but rarely, I observe that Rgui.exe terminates with 
"Error: C stack usage is too close to the limit". Unfortunately, I 
cannot reproduce the stack error consistently.

On the "old" Rgui.exe version 4.1.2, execution time stays roughly 
constant over consecutive calls of foo (as expected). Unfortunately, 
I do not have a running 4.1.3 version; thus, I cannot tell how it 
behaves there.

Do you have any clue why this happens?

Kind regards,
Tobias


#------------------------------
# minimal working example: interestingly, the issue does not occur
# when 'style = 1' in txtProgressBar()
foo <- function(n)
{
???? p_bar <- txtProgressBar(style = 3)
???? for (i in 1:n) {
???????? Sys.sleep(0.01)
???????? setTxtProgressBar(p_bar, i / n)
???? }
???? close(p_bar)
}
# 1st call
system.time(foo(100))
# 2nd call
system.time(foo(100))
# 3rd call
system.time(foo(100))
#------------------------------


My R versions:

"Old" Rgui.exe
???? R version 4.1.2 (2021-11-01)
???? Platform: x86_64-w64-mingw32/x64 (64-bit)
???? Running under: Windows 10 x64 (build 19044)

"New" Rgui.exe
???? R version 4.2.0 (2022-04-22 ucrt)
???? Platform: x86_64-w64-mingw32/x64 (64-bit)
???? Running under: Windows 10 x64 (build 19044)


------------------------------------------------------------------
Fachhochschule Nordwestschweiz FHNW
Hochschule f?r Wirtschaft
Institute for Competitiveness and Communication
Empirische Wirtschafts- und Sozialforschung

Prof. Dr. Tobias Schoch
Riggenbachstrasse 16
CH-4600 Olten
Schweiz / Switzerland
------------------------------------------------------------------
T +41 62 957 21 02
Mail tobias.schoch at fhnw.ch
http://www.fhnw.ch/de/personen/tobias-schoch