Thanks for your analysis for me Andrew. I can't use "-j" options, i think the reason is the project i dealed with is not parallel. Thus when i use "make -jN", it couldn't work correctly every time. Obviously it caused by the Makefile generated by CMake, so i wonder if there are some CMake options to use CPU effectively. Because i found when i use already exist Makefile, just use "make", it used about 480% CPU. And when i use CMake generated Makefile, it just uesd about 96% CPU. The "hardware acceleration" i said means how to CPU more effectively in CMake.
Thanks again, Chao Andrew Melo wrote > On Tue, Jul 12, 2016 at 10:48 PM, Chaos Zhang < > zcsd2012@ > > wrote: >> Thanks for your reply Raymond, by 'If you got 96% both times, then I >> would >> say there's a problem.', did you mean if make performed like this, it >> means >> this project can't use make -jN? > > If "make -j1" and "make -j8" ran in the same amount of time, there > would be a problem. Since "make -j1" uses 96% CPU and "make -j8" uses > 690% CPU, it implies that the "-j" options make compilation time > scale, which is what you want. > >> BTW, does CMake support some options to >> turn on hardware acceleration? > > What do you mean by "hardware acceleration"? > > > >> >> Raymond Wan-2 wrote >>> Hi Chao, >>> >>> >>> On Wed, Jul 13, 2016 at 10:54 AM, Chaos Zhang < >> >>> zcsd2012@ >> >>> > wrote: >>>> I was trying to compile my project using CMake, after CMake generated >>>> Makefile. >>>> I used `/usr/bin/time -v make` to make the Makefile, got the result: >>>> 'Percent of CPU this job got: 96%'. >>>> Then i used `/usr/bin/time -v make -j8` to make the Makefile, the >>>> result >>>> of >>>> CPU used is 'Percent of CPU this job got: 648%'. >>>> So i wonder if Makefile generated by CMake support make -jN, BTW my CPU >>>> is >>>> I7-4790, and after i use 'cat /proc/cpuinfo', there are 8 processors. >>> >>> >>> I'm not sure what you are asking... >>> >>> You ran make with -j 8 and you got a percentage greater than 96% ... >>> this implies that the Makefile does support -jN, doesn't it? If you >>> got 96% both times, then I would say there's a problem. >>> >>> Is what you're wondering why it is 648% and not 800%? I think that >>> depends on the dependencies in your Makefile. It's possible that some >>> of them depend on each other in such a way that 8 parallel threads is >>> not possible. >>> >>> Also, I can't remember the value returned by /usr/bin/time -v, but I >>> guess 648% is the average and not maximum. So, perhaps there are >>> parts within the Makefile that only one thread could be used and then >>> it gets averaged out? >>> >>> Ray >>> -- >>> >>> Powered by www.kitware.com >>> >>> Please keep messages on-topic and check the CMake FAQ at: >>> http://www.cmake.org/Wiki/CMake_FAQ >>> >>> Kitware offers various services to support the CMake community. For more >>> information on each offering, please visit: >>> >>> CMake Support: http://cmake.org/cmake/help/support.html >>> CMake Consulting: http://cmake.org/cmake/help/consulting.html >>> CMake Training Courses: http://cmake.org/cmake/help/training.html >>> >>> Visit other Kitware open-source projects at >>> http://www.kitware.com/opensource/opensource.html >>> >>> Follow this link to subscribe/unsubscribe: >>> http://public.kitware.com/mailman/listinfo/cmake >> >> >> >> >> >> -- >> View this message in context: >> http://cmake.3232098.n2.nabble.com/Does-Makefile-generated-by-CMake-support-make-jN-tp7593949p7593951.html >> Sent from the CMake mailing list archive at Nabble.com. >> -- >> >> Powered by www.kitware.com >> >> Please keep messages on-topic and check the CMake FAQ at: >> http://www.cmake.org/Wiki/CMake_FAQ >> >> Kitware offers various services to support the CMake community. For more >> information on each offering, please visit: >> >> CMake Support: http://cmake.org/cmake/help/support.html >> CMake Consulting: http://cmake.org/cmake/help/consulting.html >> CMake Training Courses: http://cmake.org/cmake/help/training.html >> >> Visit other Kitware open-source projects at >> http://www.kitware.com/opensource/opensource.html >> >> Follow this link to subscribe/unsubscribe: >> http://public.kitware.com/mailman/listinfo/cmake > > > > -- > -- > Andrew Melo > -- > > Powered by www.kitware.com > > Please keep messages on-topic and check the CMake FAQ at: > http://www.cmake.org/Wiki/CMake_FAQ > > Kitware offers various services to support the CMake community. For more > information on each offering, please visit: > > CMake Support: http://cmake.org/cmake/help/support.html > CMake Consulting: http://cmake.org/cmake/help/consulting.html > CMake Training Courses: http://cmake.org/cmake/help/training.html > > Visit other Kitware open-source projects at > http://www.kitware.com/opensource/opensource.html > > Follow this link to subscribe/unsubscribe: > http://public.kitware.com/mailman/listinfo/cmake -- View this message in context: http://cmake.3232098.n2.nabble.com/Does-Makefile-generated-by-CMake-support-make-jN-tp7593949p7593955.html Sent from the CMake mailing list archive at Nabble.com. -- Powered by www.kitware.com Please keep messages on-topic and check the CMake FAQ at: http://www.cmake.org/Wiki/CMake_FAQ Kitware offers various services to support the CMake community. For more information on each offering, please visit: CMake Support: http://cmake.org/cmake/help/support.html CMake Consulting: http://cmake.org/cmake/help/consulting.html CMake Training Courses: http://cmake.org/cmake/help/training.html Visit other Kitware open-source projects at http://www.kitware.com/opensource/opensource.html Follow this link to subscribe/unsubscribe: http://public.kitware.com/mailman/listinfo/cmake
