Re: gnulib-tool: Ensure that long-running tests are executed last

[Jim Meyering]

Bruno Haible wrote:
> Hi Eric, Jim,
>
>> >> This ensures that long-running tests are executed last. So that the user
>> >> gets the maximum of information as quickly as possible.
>> >
>> > That goes counter to the idea of parallel execution, where you want the
>> > long-running tests front-loaded so that the shorter tests can fill in
>> > the gaps.  If the long-running tests are last, then the entire parallel
>> > operation is stuck waiting for the last test.
>>
>> I have deliberately reordered some tests to put long-running
>> ones early enough so that a parallel (often -j5 or more) build
>> completes as quickly as possible.
>
> Hmm, it seems we are trying to optimize for different execution models and
> different goals:
>   - I was assuming a sequential execution (since this is the default with
>     "make") and the goal of maximizing the information that is available
>     within a short time after starting the test.
>   - You are assuming a parallel execution with several processors, and

No need for several processors.
If a single one of your tests does a "sleep 1",
then "make -j2" is almost guaranteed to be beneficial.
Some of our tests sleep for many seconds, but we've been
trying to avoid that.