OpenJDK ARM build not using all the CPU cores

[Mani Sarkar]

Thanks Erik we applied that flag and it has picked up the cores, we wll see
when the build finishes how much or how long it took to finish compared to
our previous 1-3 hour builds.

On Wed, 19 Apr 2017 at 11:09 Mani Sarkar <sadhak001 at gmail.com> wrote:

> Thanks Erik, I have updated our scripts with this flag.
>
> Cheers,
> Mani
>
> On Wed, 19 Apr 2017 at 10:29 Erik Joelsson <erik.joelsson at oracle.com>
> wrote:
>
>> 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.
>> >>>
>> >>> --
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