zero build slow

[Thomas Stüfe]

On Wed, Nov 22, 2017 at 6:09 PM, Erik Joelsson <erik.joelsson at oracle.com>
wrote:

> Hello,
>
> On 2017-11-22 08:30, Thomas Stüfe wrote:
>
>> On Wed, Nov 22, 2017 at 4:40 PM, Andrew Haley <aph at redhat.com> wrote:
>>
>> On 22/11/17 15:29, Thomas Stüfe wrote:
>>>
>>>> when building zero on Linux x64, I notice that the build is extremely
>>>>
>>> slow,
>>>
>>>> due to what I assume is jmod ran from the built image, which would only
>>>>
>>> run
>>>
>>>> interpreted? Is my guess true, and if yes, is it possible to use a
>>>> different jmod? I assume it is not possible to use jmod from the build
>>>>
>>> jdk?
>>>
>>> No, because the bootstrap JDK is version N-1.
>>>
>>>
>>> Ah, right.
>>
>>
>> Hmm, I wonder if you could cross-compile the JDK from x86 native -> x86
>>> zero.
>>>
>>> Does it have to be from the same build? If I build zero and normal
>> product
>> from the same head, could I not use the jmod from the product build for
>> zero?
>>
>> Yes you can indeed! There is a configure option:
>
>   --with-build-jdk        path to JDK of same version as is being built[the
>                           newly built JDK]
>
> If set, this jdk is used instead of the newly built jdk for any tool that
> needs to run, like jmod and jlink. I realize the help text could be more
> elaborate in explaining this. This option is meant for your usecase as well
> as an option to speed up cross compilation builds. (When cross compiling,
> we otherwise have to build a minimal jdk for the host system to run jmod
> and jlink during the build.)
>
> Note that for best performance, point this to the images/jdk directory of
> the release (non debug) build of the jdk for the native platform. Also note
> that it's only guaranteed to work if you use the exact same version as you
> are building zero from. If your build-jdk gets stale, weird things can
> start happening.
>
>
:) precisely what I needed, thank you!

..Thomas


> /Erik
>