OpenJDK G1 Patch

Ruslan Synytsky synytskyy at
Tue May 22 09:20:59 UTC 2018

On 22 May 2018 at 03:50, Kirk Pepperdine <kirk at> wrote:

> On May 21, 2018, at 6:15 PM, Ruslan Synytsky <synytskyy at>
> wrote:
> Dear Kirk, thank you for the feedback. Please see inline.
> On Mon, May 21, 2018 at 07:45 Kirk Pepperdine <kirk at> wrote:
>> Hi Rodrigo,
>> Interesting idea. IMHO, this solution is too simplistic as it focuses on
>> the needs of providers at the detriment of the goals of the consumers.
> I’m very concerned on this statement. Which part of the patch description
> gives you the feeling that this work has been done in favor of providers?
> Believe me, based on my experience of working with hosting providers
> worldwide, cloud vendors are least interested in resource usage
> optimization, because more resources customers use more money they pay. So,
> please give us a hint how the description can be improved.
> Well, I do have to apologize as my comment seems a bit harsh.

> *Of course reducing resources is a good thing *
Kirk, no problem. Good that we both agree on that. The main goal of this
work is to make Java less greedy on the memory usage and more cost
effective for applications with not very intensive load.

> however I have this aversion to full stop the world collections when using
> a concurrent collection. It feels like there should be a solution that
> doesn’t require calling for a full. I’m sure it won’t be as easy as calling
> for a full.
I agree too that it will be great to have a solution w/o calling Full GC.
This is why I personally like Shenandoah.

>From other side, the current patch solves the problem good enough, because
customers do not really care how it works inside, the mass market users
calculate how much money they pay for the cloud hosting and how it compares
to the resource usage with another languages. If anyone hits performance
issues, it requires a deep dive into various of options and a fine tuning
of JVM is needed anyway. The desired behavior is to tigger RAM compaction
and release *only at an idle stage and only when it's enabled*. There are
additional options that should prevent executing Full GC at an active

*MaxLoadGC - Max CPU usage that should still trigger periodic GCs. Above
this value, no periodic GC will not be triggered.*
*MaxOverCommitted - guarantees that Full GC is not triggered if memory if
not overcommitted and there is nothing to release back to OS. *
Even PHP-FPM implemented options that allow users to choose a most
convenient configuration: static - for a high performance, dynamic - for
load with predictable spikes, and ondemand - for cost efficiency (related
 and official documentation
<>). Why should we
limit Java users and force everyone to think in terms of high performance
only and always? Java users are struggling with no solution for cost
efficiency for years.


> Regards,
> Kirk

CEO @ Jelastic <>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <>

More information about the hotspot-gc-dev mailing list