[R] help.start() caused high CPU loading

[Jinsong Zhao]

I also test the same operations on R 3.6.3. The CPU usage does not 
change dramatically.

C:\Users\Jinso>typeperf "\Process(Rgui)\% Processor Time" -si 5
...
"04/28/2020 13:42:41.007","-1"
"04/28/2020 13:42:46.017","-1"
"04/28/2020 13:42:51.037","0.622240"
"04/28/2020 13:42:56.048","0.000000"
"04/28/2020 13:43:01.058","1.871148"
"04/28/2020 13:43:06.069","3.436832"
"04/28/2020 13:43:11.079","0.000000"
"04/28/2020 13:43:16.099","0.000000"
"04/28/2020 13:43:21.109","0.000000"
"04/28/2020 13:43:26.119","3.432397"
"04/28/2020 13:43:31.129","0.000000"
"04/28/2020 13:43:36.139","0.935587"
"04/28/2020 13:43:41.149","0.933886"
"04/28/2020 13:43:46.168","1.244979"
"04/28/2020 13:43:51.188","4.054443"
"04/28/2020 13:43:56.209","0.000000"
"04/28/2020 13:44:01.239","0.310505"
...

At 51", start Rgui, and 06" call help.start() from menu of Rgui, click 
on the ``Packages'' link, close browser, and so on. You may notice that 
there are no high CPU usage occurred.

Seems a bug in R 4.0.0...

Best,
Jinsong

On 2020/4/28 13:39, Jinsong Zhao wrote:
>> Again, if R was using 25% while showing the prompt and waiting for
>> user input, that would be a bug in R.
> 
> 25% CPU is used by R. And R shows the prompt and waits for user input.
> 
> Here is a report of the CPU usage by Rgui from Windows command line:
> C:\Users\Jinso>typeperf "\Process(Rgui)\% Processor Time" -si 5
> ....
> "04/28/2020 13:31:05.895","-1"
> "04/28/2020 13:31:10.915","0.622494"
> "04/28/2020 13:31:15.925","0.000000"
> "04/28/2020 13:31:20.935","0.000000"
> "04/28/2020 13:31:25.945","0.000000"
> "04/28/2020 13:31:30.965","2.801177"
> "04/28/2020 13:31:35.975","37.418638"
> "04/28/2020 13:31:40.982","100.159072"
> "04/28/2020 13:31:45.987","99.887614"
> "04/28/2020 13:31:50.992","99.899896"
> "04/28/2020 13:31:55.999","119.270784"
> "04/28/2020 13:32:01.002","299.014789"
> "04/28/2020 13:32:06.007","299.666184"
> "04/28/2020 13:32:11.015","294.905707"
> "04/28/2020 13:32:16.019","299.755921"
> "04/28/2020 13:32:21.025","299.924392"
> "04/28/2020 13:32:26.030","296.594191"
> "04/28/2020 13:32:31.048","298.195791"
> "04/28/2020 13:32:36.054","292.362986"
> "04/28/2020 13:32:41.064","292.503832"
> "04/28/2020 13:32:46.068","301.650976"
> ...
> ...
> 
> At about 10", I start Rgui, the CPU usage is about 0.5~1% (The second 
> column number may be divided by 4).
> 
> At about 35", I call help.start() from menu of Rgui, you may notice that 
> CPU usage increased to about 25%.
> 
> At about 55", I click on the ``Packages'' link in the browser. The CPU 
> usage increased to about 70-75%, and closing browser does not have any 
> effects on the CPU usage of R.
> 
>