OpenJDK ARM build not using all the CPU cores (original) (raw)

Erik Joelsson erik.joelsson at oracle.com
Wed Apr 19 09:26:46 UTC 2017

If you want to do the override at configure time, the correct configure parameter is --with-jobs=4. The --with-num-cores isn't all that useful except for easier testing of the logic for calculating the default number of jobs (which is why I left it there).

The default limitation of jobs based on memory is rather conservative (1 job per 1024MB IIRC). We don't like to assume that building is the only thing the system ever does. Also most of the build tasks aren't that memory hungry, but some are. I recommend you try manually increasing jobs until you find your optimal level of concurrency for the types of builds you do.

/Erik

On 2017-04-19 11:07, Ioi Lam wrote:

If you really want, you can override the settings with

make JOBS=4 images Of course, YMMV due to the low amount of memory. Ioi

Mani Sarkar <sadhak001 at gmail.com> 於 2017年4月19日 下午4:07 寫道：

Thanks Andrew for clarifying.

On Wed, 19 Apr 2017 at 08:56 Andrew Haley <aph at redhat.com> wrote:

On 19/04/17 08:42, Mani Sarkar wrote: Whilst build OpenJDK (latest version from http://hg.openjdk.java.net/jdk8u/jdk8u/), we have noticed, that the build system does not make use of all the CPU cores available on the machine even though it detects them all. It's because you have almost no memory installed. If you want to override the number of cores to use you can do so manually, but the idea is to prevent you from running out of memory during the build. It's deliberate, not a bug. Andrew. -- @theNeomatrix369 <http://twitter.com/theNeomatrix369>* | **Blog <http://neomatrix369.wordpress.com/>** | *LJC Associate & LJC Advocate (@adoptopenjdk & @adoptajsr programs) *Meet-a-Project - *MutabilityDetector <https://github.com/MutabilityDetector>* | **Bitbucket <https://bitbucket.org/neomatrix369>* * | **Github <https://github.com/neomatrix369>* * | **LinkedIn <http://uk.linkedin.com/pub/mani-sarkar/71/a77/39b>* Come to Devoxx UK 2017: http://www.devoxx.co.uk/ *Don't chase success, rather aim for "Excellence", and success will come chasing after you!*

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