[Skiboot] [PATCH 1/6] core/test: run trace test last

Stewart Smith stewart at linux.vnet.ibm.com
Mon Jul 10 19:54:48 AEST 2017

Oliver <oohall at gmail.com> writes:
> On Wed, Jul 5, 2017 at 11:22 AM, Stewart Smith
> <stewart at linux.vnet.ibm.com> wrote:
>> Oliver O'Halloran <oohall at gmail.com> writes:
>>> The trace test takes the longest to run and is among the least useful
>>> of the tests. Run it last so we're not stuck waiting for it when
>>> some other test is more interesting.
>>> Signed-off-by: Oliver O'Halloran <oohall at gmail.com>
>>> ---
>>>  core/test/Makefile.check | 6 ++++--
>>>  1 file changed, 4 insertions(+), 2 deletions(-)
>> Does this change really make a difference? You're running 'make check'
>> with -j, right?
> It makes a difference when running on my laptop. It looks like when
> `nproc` is less than the number of dependencies of the make target it
> still runs them in order. The trace test ties up a core for a while so
> moving it to last still speeds things up a bit.

nproc is possibly also a single digit number, which is never a fun place
to be in. Mere double digits seems small and constrained these days...

I didn't see an improvement on my laptop, but then again, I generally 2x
nproc just to make the scheduler work for its dinner.

So, at least currently I don't see this regressing the test time
(although that could just be because we've added a bunch of tests and
duplicated things for p8/p9).

> Besides, on a build box with a lot of threads it's sometimes nice to
> run it with -j1 just so you don't have to sift through the scroll back
> to locate errors.

Yeah, that use case is always valid.

Stewart Smith
OPAL Architect, IBM.

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