[R-pkg-devel] Re-building vignettes had CPU time 9.2 times elapsed time

[Duncan Murdoch]

On 25/08/2023 6:13 p.m., Toby Hocking wrote:
> Thanks Dirk. I agree.
> data.table is not in a situation to update very soon, so the easiest
> solution for the R community would be for CRAN to set OMP_THREAD_LIMIT
> to 2 on the Windows and Debian machines doing this test.
> Otherwise the 1400+ packages with hard dependencies on data.table will
> each have to implement custom logic to limit threads to 2.

That doesn't follow.  data.table could update soon even if that wasn't 
their intention:  just include bug fixes and set the default 
OMP_THREAD_LIMIT to 2 in data.table.

The real problem is that there are two stubborn groups opposing each 
other:  the data.table developers and the CRAN maintainers.  The former 
think users should by default dedicate their whole machine to 
data.table.  The latter think users should opt in to do that.

Duncan Murdoch

> Toby
> 
> On Fri, Aug 25, 2023 at 6:46 AM Dirk Eddelbuettel <edd using debian.org> wrote:
>>
>>
>> On 24 August 2023 at 07:42, Fred Viole wrote:
>> | Hi, I am receiving a NOTE upon submission regarding the re-building of
>> | vignettes for CPU time for the Debian check.
>> |
>> | I am unable to find any documented instances or solutions to this issue.
>> | The vignettes currently build in 1m 54.3s locally and in 56s on the Win
>> | check.
>> |
>> | https://win-builder.r-project.org/incoming_pretest/NNS_10.1_20230824_132459/Debian/00check.log
>>
>> Please see, inter alia, the long running thread
>>
>>     "Trouble with long-running tests on CRAN debian server"
>>
>> started earlier this week (!!) on this list covering exactly this issue.
>>
>> We can only hope CRAN comes to understand our point that _it_ should set a
>> clearly-identifable variable (the OpenMP thread count would do) so that
>> package data.table can this for its several hundred users.
>>
>> As things currently stand, CRAN expects several hundred packages (such as
>> your, guessing there this comes from data.table which I do not know for sure
>> but you do import it) to make the change which is pretty close to the text
>> book definition of madness.
>>
>> Also see https://github.com/Rdatatable/data.table/issues/5658 with by now 24
>> comments.  It is on the same issue.
>>
>> Uwe, Kurt: Please please please set OMP_THREAD_LIMIT to 2 on the Windows and
>> Debian machines doing this test.
>>
>> Dirk
>>
>> --
>> dirk.eddelbuettel.com | @eddelbuettel | edd using debian.org
>>
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