On Mon, Jan 29, 2018 at 5:48 PM, Thomas Munro
<thomas.munro@enterprisedb.com> wrote:
> On Mon, Jan 29, 2018 at 5:35 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> Thomas Munro <thomas.munro@enterprisedb.com> writes:
>>> Does anyone have any thoughts on why Travis CI might be failing
>>> occasionally as shown below, but the build farm apparently doesn't?
>>> It's not alien technology, it's just Ubuntu Linux running on a virtual
>>> machine. One thing that it does slightly differently is "make
>>> -Otarget -j3 check-world" but I don't see why -j3 would break
>>> something like that specifically, except perhaps by overloading the
>>> system in a way that affects timing.
>>
>> Quite a few of us use -jsomething with make check-world, so I doubt
>> that that's an issue per se. I have no idea what -Otarget means in
>> this context though, and neither does "info make".
>
> -Otarget means that it should buffer the output from all the parallel
> jobs and then serialise them into per-target chunks, so that you can
> read the output instead of getting intermingled lines from concurrent
> stuff. I learned this trick from Andres... I think it landed in GNU
> make 4.something, so it's quite new. The latest web documentation
> only says that it exists, and doesn't say what it does!
>
> https://www.gnu.org/software/make/manual/make.html
Oh, actually it is now documented:
‘-O[type]’
‘--output-sync[=type]’
Ensure that the complete output from each recipe is printed in one
uninterrupted sequence. This option is only useful when using the
--jobs option to run multiple recipes simultaneously (see Parallel
Execution) Without this option output will be displayed as it is
generated by the recipes.
With no type or the type ‘target’, output from the entire recipe of
each target is grouped together. With the type ‘line’, output from
each line in the recipe is grouped together. With the type ‘recurse’,
the output from an entire recursive make is grouped together. With the
type ‘none’, no output synchronization is performed. See Output During
Parallel Execution.
--
Thomas Munro
http://www.enterprisedb.com