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From "Nikolay Kuznetsov" <nikolay.kuznet...@gmail.com>
Subject Re: [drlvm][gc] TLS access from GC: a proposal to refactor the code
Date Wed, 25 Oct 2006 09:46:16 GMT
Hello All,

in general we do not have any objections to implement such
functionality, but as far as I understand this will be quite unique TM
feature (no other threading library have this, or give me a link)
which is intended to improve performance. And if we going to extend TM
interface for this, I would like to have  any performance data
beforehand, do we any data?

Thank you.
   Nik.

On 10/25/06, Ivan Volosyuk <ivan.volosyuk@gmail.com> wrote:
> 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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