Pierre Labastie wrote:
Le 25/11/2014 16:26, Bruce Dubbs a écrit :
Pierre Labastie wrote:
On my machine at work, letting the build system choose how many parallel
jobs to launch (configure found 14), here are the timings for
configure+make:
----------------------
Finished building OpenJDK for target 'all'
real 9m45.357s
user 55m28.092s
sys 2m22.024s
---------------------
which I understand as ~ 10 mn real time for ~ 1 h processor time. A gain
of almost 6x. Not too bad. On this machine, the SBU is ~165 s, so using
all the cores allow to be below 4 SBUs.
It would be interesting to know how long LibreOffice takes. The time
for gcc tests would be interesting too.
Before that, the figures for --with-jobs=1:
-------------------------
Finished building OpenJDK for target 'all'
real 26m13.905s
user 42m31.244s
sys 1m44.248s
------------------------
so it looks like real time is ~half cpu time... So maybe, there are
still parallel jobs somewhere, or I do not understand the "time" command
output.
The usage is (u+s)/r. In the j1 case that's about 169%,
For j14, it's about 593%.
Any job has a portion that cannot be done in parallel and many times the
prerequisites will limit the number of jobs running at one time.
-- Bruce
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