Slides for our presentation at the Bucharest Technology Week

Tobias Hartmann tobias.hartmann at
Mon May 30 12:53:44 UTC 2016

Hi Remi,

On 30.05.2016 14:36, Remi Forax wrote:
> Hi Tobias,
> very nice set of slides, better than mine on tiered compilation.
> I think you should upload it on the Hotspot wiki for the future generation.

Thank you! We'll discuss that.

> There is one thing which is not clear to me at the end of the second part,
> in the LogLineBench, what policy did you use for String concatenation, is it one that use a StringBuilder or one that use method handles ?

This example is from Aleksey's jfokus presentation (I used it with his consent, see [1], slide 48). Those measurements were done right after Compact Strings integration (JDK 9 b93) before Indify String Concat. I wanted to focus on Compact Strings, in Aleksey's slides you can also find measurements with ISC.

> and BTW, part of the 'bloat' in the code cache also comes from the lambda forms compilation.

Yes, I actually mentioned this in the talk.

Best regards,


> regards,
> Rémi
> ----- Mail original -----
>> De: "Tobias Hartmann" <tobias.hartmann at>
>> À: "Vladimir Ivanov" <vladimir.x.ivanov at>
>> Cc: hotspot-compiler-dev at, "hotspot compiler staff ww grp" <hotspot_compiler_staff_ww_grp at>
>> Envoyé: Lundi 30 Mai 2016 12:21:06
>> Objet: Re: Slides for our presentation at the Bucharest Technology Week
>> Hi Vladimir,
>> On 30.05.2016 12:04, Vladimir Ivanov wrote:
>>> Nice slide deck!
>>> I suggest to post the link on open list as well.
>> Thank you! I CC'ed hotspot-compiler-dev.
>> Best regards,
>> Tobias
>>> On 5/30/16 10:12 AM, Tobias Hartmann wrote:
>>>> Hi,
>>>> Zoltan and I gave a talk about "The Java HotSpot VM - Under the Hood" at
>>>> the Bucharest Tech Week [1] last Friday. We introduced the (compiler)
>>>> internals of the VM and presented two of the new features for JDK 9
>>>> (Segmented Code Cache and Compact Strings).
>>>> In case you are interested, here are the slides:
>>>> Best regards,
>>>> Tobias
>>>> [1]

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