Future plans for AppCDS?

[Vladimir Kozlov]

Here is very good and detailed blog about what you can do with AppCDS and AOT:

https://mjg123.github.io/2017/10/04/AppCDS-and-Clojure.html

Regards,
Vladimir

On 11/28/17 2:03 AM, Volker Simonis wrote:
> Hi Mike,
> 
> what you are actually asking for is support for AOT (Ahead Of Time
> compilation) [1].
> 
> It is already available in Java 9.  Although the support for user code
> is still experimental you should definitely give it a try.
> 
> Regards,
> Volker
> 
> [1] http://openjdk.java.net/jeps/295
> 
> 
> On Tue, Aug 4, 2015 at 8:23 PM, Mike Hearn <hearn at vinumeris.com> wrote:
>> Hi there,
>>
>> I'm wondering if there are any plans to extend AppCDS in future to include
>> serializing the code cache to disk?
>>
>> I ask because I have a (not very complicated) desktop JavaFX app. It starts
>> in about three seconds, which isn't terrible, but I'd like it to be faster.
>>
>> Unfortunately I am frequently frustrated in this goal.  Some testing shows
>> that one step of the initialisation sequence takes about a second normally.
>> If I put it in a loop to let it fully compile, that drops to more like a
>> quarter of a second.
>>
>> Likewise, my app loads a series of items to display them on the screen. The
>> first one can take a solid 700-800 msec. The rest are more like 10% of that.
>>
>> I tried parallelising some of the things done during startup, but it made
>> no difference. My theory is that the compile threads are taking up the
>> spare cores that could be doing startup tasks (it's a bit hard to profile
>> this though as the whole sequence only lasts a few seconds).
>>
>> AppCDS already knows how to serialise lots of HotSpot state to disk for
>> unchanging JARs. If it could store compiled method code as well, then I
>> could probably shave a second or two off app startup.
>>
>> I do understand that this situation is a bit rare for Java developers and
>> that due to extra disk IO etc, loading compiled code from disk might not
>> always be faster. But for devices that have an SSD it probably can be,
>> especially if HotSpot were to do the same trick Microsoft does and lay out
>> compiled methods on disk in the order they will be used.