Loom prototype publicly available

[Martijn Verburg]

Makes sense - LMK when you want to pull the trigger ��

On Wed, 8 Aug 2018 at 11:06, Ron Pressler <ron.pressler at oracle.com> wrote:

> Thanks, Martijn!
> That can certainly be a good idea, but at a later point, when we have a
> better sense of the design.
> I fear that making Loom too accessible at this early stage in the design
> may cause a barrage of bikeshed suggestions.
>
> Ron
>
>
> On August 7, 2018 at 4:29:52 PM, Martijn Verburg (martijnverburg at gmail.com)
> wrote:
>
> Hi Ron et al,
>
> Would you like Project Loom builds at AdoptOpenJDK.net?  We build Amber
> (raw string literals branch).  Happy to add Loom if that suits.
>
> Cheers,
> Martijn
>
>
> On Fri, 3 Aug 2018 at 01:38, Ron Pressler <ron.pressler at oracle.com> wrote:
>
>> Yes, the current implementation is “one shot” (and a one-shot delimited
>> continuation is often also known as a coroutine), and cannot be used to
>> implement amb. However, we may make the continuations cloneable in which
>> case they can be used to implement amb.
>>
>>
>> On July 30, 2018 at 9:03:16 AM, Ryan Schmitt (rschmitt at pobox.com) wrote:
>>
>> This is a fascinating prototype. Would it be correct to describe Loom's
>> continuations as "one-shot" continuations? Should it be possible to
>> implement the `amb` operator on this prototype?
>>
>> On Fri, Jul 27, 2018 at 10:51 AM, Ron Pressler <ron.pressler at oracle.com>
>> wrote:
>> Hi.
>>
>> You can now build and try our initial Loom prototype.
>>
>>         $ hg clone http://hg.openjdk.java.net/loom/loom
>>         $ cd loom
>>         $ hg update -r fibers
>>         $ sh configure
>>         $ make images
>>
>> (Note that you must switch to the fibers branch)
>>
>> - Supported platforms: Mac and Linux on x86-64
>> - Tested GCs: Parallel and G1
>> - Supported compilers: C1, C2, Graal
>> - Missing features: JVM TI (fiber debugging), fiber/continuation
>> serialization
>>
>> Work on tail calls has not yet begun.
>>
>> Current status will be tracked in a wiki page we will set up soon.
>>
>> The fibers API is in the java.lang.Fiber class, and is minimal at this
>> stage.
>> Thread locals should work as expected (and be associated with the fiber),
>> and
>> calls to Thread.currentThread() would return a consistent result, so a
>> lot of
>> existing code should work. Most relevant IO operations, as well as
>> java.util.concurrent constructs, Thread.sleep etc. will now result in the
>> fiber
>> — rather than the underlying kernel thread — being blocked.
>>
>> Object.wait() would still block the underlying kernel thread, as would
>> trying to
>> park a fiber while a native monitor is held or a native method is on the
>> stack.
>>
>> The current implementation performs a full stack copy by default. To
>> experiment
>> with the lazy-copying solution I described in a previous email, add
>> `-XX:+UnlockExperimentalVMOptions -XX:+UseNewCode`, but note that in that
>> mode
>> exceptions thrown inside continuations may not work (probably crash the
>> VM) and
>> stack traces would be missing frames.
>>
>> This is an initial prototype made to be simple to implement so we could
>> experiment with different APIs, compatibility etc.. Performance,
>> therefore, is
>> far from stellar. Designing a good API and writing an implementation with
>> good
>> performance are our top priorities.
>>
>> You’re welcome to try the prototype and share your impressions here. On
>> Monday,
>> we’ll present Loom at JVMLS, and more updates will follow.
>>
>>
>> Ron
>>
>>
>>
>>
>> --
Cheers, Martijn (Sent from Gmail Mobile)