Building CPython

[Terry Reedy]

On 5/15/2015 6:51 AM, Christian Gollwitzer wrote:
> Am 14.05.15 um 20:50 schrieb Terry Reedy:
>> On 5/14/2015 1:11 PM, Chris Angelico wrote:
>>
>>> 2) make test - run the entire test suite. Takes just as long every
>>> time, but most of it won't have changed.
>>
>> The test runner has an option, -jn, to run tests in n processes instead
>> of just 1.  On my 6 core pentium, -j5 cuts time to almost exactly 1/5th
>> of otherwise.  -j10 seems faster but have not times it.  I suspect that
>> 'make test' does not use -j option.
>>
>
> Just to clarify, -j is an option of GNU make to run the Makefile in
> parallel. Unless the Makefile is buggy, this should result in the same
> output. You can also set an environment variable to enable this
> permanently (until you log out) like
>
> export MAKEFLAGS=-j5
>
> Put this into your .bashrc or .profile, and it'll become permanent.

This is not applicable when running on Windows.  I was specifically 
referring, for instance, to entering at command prompt

current_dir> python -m test -j10

AFAIK, test.__main__ does not look at environmental variables.

ps. I have been wondering why 'j' rather than, say 'c' or 'p' was used 
for 'run in parallel on multiple cores'.  Your comment suggests that 'j' 
follows precedent.

-- 
Terry Jan Reedy