Re: FW: Release Notes for Beignet Version 0.1

["Zhigang Gong" <zhigang.gong@linux.intel.com>]

> -----Original Message-----
> From:
> intel-gfx-bounces+zhigang.gong=linux.intel.com@lists.freedesktop.org
> [mailto:intel-gfx-bounces+zhigang.gong=linux.intel.com@lists.freedesktop.
> org] On Behalf Of Zou, Nanhai
> Sent: Tuesday, April 16, 2013 2:47 PM
> To: Dave Airlie
> Cc: intel-gfx@lists.freedesktop.org
> Subject: Re: [Intel-gfx] FW: Release Notes for Beignet Version 0.1
> 
> Hi,
> 
> > Again not really important, we use LLVM and TGSI backends in the
> radeon drivers now. The gallium drivers currently use GPU specific LLVM
> IRs produced from specific LLVM backends, but that isn't strictly
necessary
> just leads to better optimising opportunities.
> > Because you now have a whole bunch of code that is useless to anyone
> else. Distro want to ship this sort of thing, we don't want 5 Mesa like
> implementations for OpenCL, we want one we can actually distribute and
> manage, and >maybe in 5 years support.
> 
> 	The point is at the current stage, we don't see the necessary of
> introduce all those complexity and dependencies.
> 	Considering we can share very few code with other part of
> Mesa(expect some GPU related define in header files).
> 
> 	We want to keep this project tiny and self-contained at this point,
> focus on make OpenCL really fast and useful on IVB+ GPU.
> 
> 	We can merge or hook the backend into gallium when there are
> other mature gallium based OpenCL implementations.
> 	That should not be a lot of task,  consider the common code are very
> few.
> 
> 
> >  Some other questions:
> >  a) have you got an ivybridge LLVM backend? are you going to upstream
> this, I heard it isn't even written in LLVM machine description format.
> 
> 	No, we convert llvm IR to Gen IR then to IVB assembly.
>     There are many choices when implement an execute model of IVB. E.g
> 8 way or 16 way, SOA mode or AOS mode.
> 	We choose 16 way AOS mode in the driver.
> 	I don't know if it make sense to upstream only this particular
> combination.
> 
> 
> >  b) have you looked at pocl, libclc etc? Maybe you guys want to run on
> CPU as well at GPU at some point, in which case maybe again looking
> around before jumping into implementing stuff might help.
> 
> 	We do have looked at libclc.
> 	Again, I don't see the necessary to introduce the complexity at this
> point
> 	Almost all the functions in libclc maps to 1 instructions on IVB. We
do
> not see the necessary of introducing a library to wrap those.
> 
> >  c) does this use the open source ICD at least?
> 	No, we will check that.
[Gong, Zhigang] As I know, Simon implemented ICD for Beignet and it may need
some time to rebase to the latest beignet code base.
If you are interested, this is the link http://psi5.com/~geier/beignet.git.
> 
> 
> Dave.
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