gold for linking

[Volker Simonis]

We've experimented with this as well a few years ago. The problem was
that it doesn't correctly support all architectures (if I remember
right there were some problems with unknown relocation types). So when
you add this we have to take care that it will be only used on
ppc/s390/aarch if it really works.

Regards,
Volker


On Mon, Mar 27, 2017 at 10:47 AM, Ioi Lam <ioi.lam at oracle.com> wrote:
>
>
> On 3/26/17 8:43 PM, Claes Redestad wrote:
>>
>> +1, at least to make it an optional setting.
>>
>> Making it heavily multi-threaded by default may be a pessimization when
>> we're doing full image builds, cf. how many of the java tools in the
>> build is using serial GC and fewer compiler threads to play nice under
>> heavy parallelism.
>>
>> Have you done any assessment on whether this has any effect on static
>> footprint and performance on the resulting images?
>>
> I haven't done any formal measurements. Anecdotally when I ran a class
> loading benchmark it shows no noticeable difference in performance. I didn't
> measure the size of the libjvm.so
>
> Thanks
> - Ioi
>
>> /Claes
>>
>> On 2017-03-26 12:30, Ioi Lam wrote:
>>>
>>> I just tried adding -fuse-ld=gold to the g++ linker flags, and my
>>> libjvm.so link time shrinks from 18 seconds to 6 seconds. And that's
>>> with single threaded linking. If I add "-Wl,--threads
>>> -Wl,--thread-count,8" it becomes 4 seconds. It doesn't seem to scale
>>> after 8 threads.
>>>
>>> Any plans for adding official (perhaps optional) support for gold in the
>>> JDK build system?
>>>
>>> Thanks
>>> - Ioi
>
>