I'd recommend opening a bug in v8's issue tracker so they're aware of this
upstream.

On Wed, Aug 25, 2010 at 4:35 AM, Bert Belder <[email protected]> wrote:

> Thanks for looking into it, I'll try the patch in a minute.
>
> In the short term it should help me because I do not need a lot more
> memory than 1GB. The biggest problem was the slowness due to V8 doing
> full GCs like crazy when it's almost out of memory, so this should
> help a little.
>
> However, do you think this could/will be fixed in the long term?
> Eventually I'd like to be able to use 16G of memory :-)
>
> - Bert
>
>
> On Aug 25, 1:06 pm, Vyacheslav Egorov <[email protected]> wrote:
> > Hi Bert,
> >
> > I did a quick look into this problem. It seems V8 currently can't handle
> > such big heaps:
> >
> > 0) Memory allocator and MarkCompact garbage collector encode certain
> things
> > in a special way so without major rewriting you can try to get at most
> >  ~1.8gb heap on x64.
> >
> > 1) Memory management code is full of integer overflows --- it uses int
> where
> > bigger type is required to handle big heap sizes. [I am attaching small
> > dirty patch to fix some of this overflows. with it you can grow heap
> almost
> > up to 1.8 gb heap]
> >
> > 2) GC pauses will be huge for huge heaps: mark-sweep will take at > 1 s,
> > mark-compact will take > 3s, scavenge throughput will also be degraded
> (it
> > needs to scan oldspaces for intergenerational pointers).
> >
> > --
> > Vyacheslav Egorov
> >
> > On Wed, Aug 25, 2010 at 10:36 AM, Bert Belder <[email protected]>
> wrote:
> > > On Aug 25, 9:57 am, Erik Corry <[email protected]> wrote:
> > > > Are you running the 64 bit version of V8?
> >
> > > I think so. To eliminate other causes I did a fresh git clone from
> > > git://github.com/v8/v8.git, then:
> > >  scons arch=x64 sample=shell
> > >  ./shell --max_old_space_size=2000000000 test.js
> >
> > > > file `which v8`
> > > ./shell: ELF 64-bit LSB executable, x86-64, version 1 (SYSV),
> > > dynamically linked (uses shared libs), for GNU/Linux 2.6.15, not
> > > stripped
> >
> > > - Bert
> >
> > > --
> > > v8-users mailing list
> > > [email protected]
> > >http://groups.google.com/group/v8-users
> >
> >
> >
> >  overflows.patch
> > 9KViewDownload
>
> --
> v8-users mailing list
> [email protected]
> http://groups.google.com/group/v8-users
>

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