[squeak-dev] [ANN] Squeak 5
btc at openinworld.com
Wed Aug 12 15:46:52 UTC 2015
On Wed, Aug 12, 2015 at 11:23 AM, Chris Muller <ma.chris.m at gmail.com> wrote:
> In the 17 months since Squeak 4.5 was released, a huge development
> effort took place to create the next generation virtual-machine for
> the Squeak / Pharo / Newspeak family of programming systems. Squeak
> is the modern incarnation of the Smalltalk-80 programming environment
> originally developed at the Xerox PARC.
> "Squeak 5" introduces this new VM and associated new memory model,
> collectively referred to as "Spur". Presented  by Eliot Miranda
> and Clément Béra at the 2015 International Symposium on Memory
> Management, this new VM affords Squeak applications a significant
> boost in performance and memory management. Among other
> optimizations, the #become operation no longer requires a memory scan.
> Object pinning and ephemerons are also now supported. The release
> notes  provide more details.
> The new memory model requires a new image file format. Although this
> new format results in about a 15% increased memory requirement for the
> same number of 4.x objects, a new segmented heap allows memory to be
> given back to the OS when its no longer needed, a great benefit for
> application servers.
> As forward compatibility is as important to the Squeak community as
> backward compatibility, Squeak 5 is delivers an image with identical
> content as the recent 4.6 release. Although this new Squeak 5 VM
> cannot open images saved under the prior 4.x Cog format, objects and
> code can be easily exported from the 4.x image and then imported into
> Squeak 5. Applications whose code runs strictly above the Smalltalk
> meta layer will prove remarkably compatible with the new format, most
> applications will require no changes whatsotever.
> Squeak 5 is the result of monumental effort by a tiny group of very
> talented people, but its also just the beginning of yet a new effort;
> Spur is just a stepping stone to a more ambitious goals planned over
> the next five years.
>  -- A Partial Read Barrier for Efficient Support of Live
> Object-oriented Programming
>  -- Squeak 5 Release Notes
Love figure 4 in the paper. Sub millisecond pause for garbage
collection of GB size images.
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