[darcs-users] darcs patch: Add Test.Runner module to run the unit t... (and 7 more)

[Trent W. Buck]

Eric Kow <kowey at darcs.net> writes:

> On Tue, May 19, 2009 at 10:17:56 -0700, Jason Dagit wrote:
>> I can't manage time for another review right now.  So please use your
>> best judgment without my further input :)  Short answer: Sure if you
>> think so.
>
> I'm afraid I'm going to have to just apply this without review.  Our
> Review Team seems to be a bit stretched right now (and I personally have
> to do a bit of catching up at work).  Need more reviewers!

I did this:

    ghc --make Setup
    ./Setup configure -ftest\ tests
    ./Setup build
    dist/build/unit/unit -j4

The output from unit is totally garbled, because multiple
threads/processes are writing to stdout at the same time.

AFAICT this makes it impossible to see which unit tests are failing AND
it makes the unit tests run far more slowly -- perhaps because most of
my CPU time is taken up trying to write the garble to stdout/stderr?

Is this a known issue?

    $ time dist/build/unit/unit >/dev/null

    real    2m45.696s
    user    2m41.740s
    sys     0m3.960s

    $ time dist/build/unit/unit -j4 >/dev/null 2>/dev/null

    real    3m53.857s
    user    3m50.170s
    sys     0m6.670s

    $ grep model.name /proc/cpuinfo
    model name      : Intel(R) Core(TM)2 Quad CPU    Q9550  @ 2.83GHz
    model name      : Intel(R) Core(TM)2 Quad CPU    Q9550  @ 2.83GHz
    model name      : Intel(R) Core(TM)2 Quad CPU    Q9550  @ 2.83GHz
    model name      : Intel(R) Core(TM)2 Quad CPU    Q9550  @ 2.83GHz

Note that with -j4 I needed to discard stderr, too.