HotSpot just got Hotter - IcedTea6 support for latest HotSpot

[Mark Wielaard]

Hi Andrew,

On Tue, 2008-12-02 at 10:51 +0000, Andrew Haley wrote:
> Mark Wielaard wrote:
> > - We want an easy mechanism for trying out newer hotspots so you can
> > easily build a newer version and let people try out performance
> > improvements or new features/flags (but on top of the stable 6 core
> > build). I really like this part of Andrew's patch, which lets you select
> > either a hg revision/version number or a prepackaged hotspot src zip.
> 
> Well, yeah, it's nice, but this isn't worth doing if the need to support
> pluggable VMs leads to cruft in other areas.

I think it is a much cleaner way than the current setup, where we carry
a giant patch (icedtea-hotspot-6b12-7b24.patch) that needs (manual)
updating whenever we update 6bxx drops. It makes any updates to the
hotspot core independent of updates of the other modules.

> > What is the best way to combine all these properties and keep our
> > maintance level as low as possible. Which hotspot version(s) to support
> > by default that make it easy to provide support for all of the above
> > requirements. Did I forget anything?
> 
> You have to ask: is this flexible configury part of the solution, or
> part of the problem?  Right now it's not clear to me.
> 
> Generally speaking, new hotspot is better than old.  We run the risk
> that multiple build options will make the system fragile.  It's much
> better, where possible, to have everyone building the same sources.

Yes. I think the major churn comes from supporting the old openjdk6
based hotspot because it needs so many backported patches, doesn't
include sparc, has a different build dir layout, and doesn't come with
the c++ interpreter for zero. It would be wise to only support newer
hotspots that have at least most of that fixed.

Cheers,

Mark