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From "Ivan Volosyuk" <ivan.volos...@gmail.com>
Subject Re: [drlvm][gc] TLS access from GC: a proposal to refactor the code
Date Wed, 25 Oct 2006 09:04:51 GMT
Xiao-Feng, I think there should be no problem to get this to work.
But, I also agree with Mikhail that it could be benefitial to have
data directly available in TLS without additional pointer dereference.
If we will have corresponding interface function to allocate more then
one void pointer at once in TLS it can be used as optimization.
--
Ivan

On 10/25/06, Xiao-Feng Li <xiaofeng.li@gmail.com> wrote:
> On 10/25/06, Mikhail Fursov <mike.fursov@gmail.com> wrote:
> > On 10/25/06, Xiao-Feng Li <xiaofeng.li@gmail.com> wrote:
> > >
> > > Why do we need multiple slots? Can't we use just one slot, which
> > > stores a pointer to a user data structure (the GC_Thread_Info in this
> > > case)?
> > >
> >
> > Yes you can store a pointer. But in this case you can't tell that you have
> > constant offset from fs[14] to your data for all threads. So you can't
> > inline your helper in JIT.
>
> Why? As long as we keep the offset_of_free to the pointer be constant
> and known to JIT helper, we only need an additional dereference to get
> the "free" value.
>
> We have two constant offsets, one is the pointer (to gc_tls_data)
> offset in fs[14], the other is the "free" offset in gc_tls_data.
>
> Thanks,
> xiaofeng
> > --
> > Mikhail Fursov

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