wrote: > Thanks for reference. > > (2011/10/26 11:20), Carter Cheng wrote: > > I noticed that you used context threading in YARV. Do you have some > analysis > > of this cost benefit wise over other methods? I was curious why you > selected > > this for ruby. > > We don't use context threading[1]. context threading needs a few > assembler codes. However, YARV doesn't use any assemblers. In current > our YARV bytecode, I doubt that we can't make it faster with it because > of instruction granularity (course-grain instruction especially "send"). > > [2] may also help you. > > > [1] Context Threading: A Flexible and Efficient Dispatch Technique for > Virtual Machine Interpreters > > http://dl.acm.org/citation.cfm?id=1048922.1048973&coll=DL&dl=GUIDE&CFID=63997736&CFTOKEN=37906754 > > [2] Analyzing the performance of code-copying virtual machines > > http://dl.acm.org/citation.cfm?id=1449764.1449796&coll=DL&dl=GUIDE&CFID=63997736&CFTOKEN=37906754 > > Regards, > Koichi > > -- > // SASADA Koichi at atdot dot net > > --bcaec54ee4445a5f6b04b03c39a9 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Thanks Koichi.

I guess when it comes to Ruby my sense is= that the dynamism poses some complex problems for development of a good JI= T system. I know that Macruby relies on the LLVM JIT system and this simpli= fies much of the coding.- however the LLVM JIT system is rather heavyweight= . There was some paper describing for example the effect of substituting (n= ot in much detail) tcg in QEMU using the LLVM system and the performance wa= s significantly impeded.

I am curious of what your sense is of this. I am somewh= at speculating here- but it would seem to me that one of the main limiting = factors (not having studied the exact sequence of instructions produced by = MRI) is the extra overhead in primitive operations due to the inability to = infer which operations to apply to a type statically and perhaps the overhe= ad associated with invoke/sends.

I may do some studies later but I am sure you have more= experience in this area than I do.

Regards,

Carter.

On Thu, Oct 27, 2011 at 5:28 AM, SASADA Koichi <ko1@atdot.net> wrote:
Thanks=E3=80=80for reference.

(2011/10/26 11:20), Carter Cheng wrote:
> I noticed that you used context threading in YARV. Do you have some an= alysis
> of this cost benefit wise over other methods? I was curious why you se= lected
> this for ruby.

We don't use context threading[1]. =C2=A0context threading needs = a few
assembler codes. =C2=A0However, YARV doesn't use any assemblers. =C2=A0= In current
our YARV bytecode, I doubt that we can't make it faster with it because=
of instruction granularity (course-grain instruction especially "send&= quot;).

[2] may also help you.

[1] Context Threading: A Flexible and Efficient Dispatch Technique for
Virtual Machine Interpreters
http://dl.acm.org/citation.cfm?id=3D1048922.1048973&coll=3DDL&d= l=3DGUIDE&CFID=3D63997736&CFTOKEN=3D37906754

[2] Analyzing the performance of code-copying virtual machines
http://dl.acm.org/citation.cfm?id=3D1449764.1449796&coll=3DDL&d= l=3DGUIDE&CFID=3D63997736&CFTOKEN=3D37906754

Regards,
Koichi

--
// SASADA Koichi at atdot dot net

--bcaec54ee4445a5f6b04b03c39a9--