Re: Cygwin Perl has slowed in recent months

[David Christensen <dpchrist@holgerdanske.com>]

On 5/24/22 01:47, Sam Edge wrote:
> On 24/05/2022 09:25, Csaba Raduly wrote:
>  > On Mon, 23 May 2022 at 20:47, Lee  wrote:
>  >>
>  >> On 5/22/22, David Christensen <dpchrist@holgerdanske.com> wrote:
>  >>> On 5/21/22 10:55, Hans-Bernhard Bröker wrote:
>  >>>> Am 18.05.2022 um 03:53 schrieb David Christensen:
>  >>>>
>  >>>>  > I am working on a Perl module that runs on various Unix-like
> platforms.
>  >>>>  > When I 'make test' on similar computers:
>  >>>>  >
>  >>>>  > FreeBSD 12.3-RELEASE         28 wallclock secs
>  >>>>  > Debian GNU/Linux 11.3          31 wallclock secs
>  >>>>  > macOS 11.6.2              36 wallclock secs
>  >>>>  > Windows 7 / Cygwin 3.3.5-1    509 wallclock secs
>  >>>>
>  >>>> Given the complete lack of information about what that Perl module of
>  >>>> yours might be doing, that's hard to have a meaningful discussion
> about.
>  >>>
>  >>>
>  >>> Thank you for the response.  I was hoping there was a known issue.
>  >>> Apparently, not.
>  >>
>  >> What I consider a well known issue is that process start up time is
>  >> _very_ slow.  If your  'make test' starts lots of processes that could
>  >> be a problem.
>  >>
>  >
>  > While Cygwin''s fork emulation is indeed  slow (I once measured 1000:1
>  > between Cygwin and Linux  * ),
>  > "make test" likely started roughly the same number of processes "then"
>  > as it does  "now".
>  > In  which case the increase in the run time could be attributed to
> Cygwin.
> 
> Indeed.
> 
> But perhaps what the Cygwin core and/or Cygwin Perl maintainers need is a
> simple test case Perl script that can be shown to be much slower on the
> current
> releases than it was on a named earlier pair of releases. And maybe some
> testing by the original poster to see if it is the Cygwin or Perl release
> change that causes the issue.
> 
> Anecdotal observations do not an issue report make. ;-)


So, we are discussing running a Perl benchmark for various combinations 
of Cygwin version and/or Cygwin Perl version.  That is an O(n) and/or 
O(n**2) problem.


If multiple benchmarks are considered, increase the O() exponent by one.


If multiple versions of Windows are considered, increase the O() 
exponent by one.


If multiple computers are considered, increase the O() exponent by one.


Does the Cygwin project do any of the above?  If so, how?  Where are the 
test plans and assets?  Where is the raw data?  Where are the reports?


If end users are expected to do the above, please advise:

1.  How to install multiple versions of Cygwin on Windows 7 Professional 
64-bit Service Pack 1 on an x86_64 computer such that each instance of 
Cygwin does not interact with any other instance of Cygwin.

2.  How to install multiple versions of Cygwin Perl on each of many 
Cygwin installations on Windows 7 Professional 64-bit Service Pack 1 on 
an x86_64 computer such that each instance of Cygwin Perl does not 
interact with any other instance of Cygwin Perl or Cygwin.

3.  What is a suitable Perl benchmark?


David