[LLVMdev] ANN: libclc (OpenCL C library implementation)

[Villmow, Micah]

Anywhere the updated numbers are posted?

Thanks,
Micah

> -----Original Message-----
> From: Ralf Karrenberg [mailto:Chareos at gmx.de]
> Sent: Wednesday, October 19, 2011 2:52 PM
> To: Villmow, Micah
> Cc: llvmdev at cs.uiuc.edu
> Subject: Re: [LLVMdev] ANN: libclc (OpenCL C library implementation)
> 
> Hi Micah,
> 
> The numbers from the paper were measured with the ATI Stream SDK v2.1
> (it's only mentioned in the references I think).
> The most recent measurements I have were done with the current v2.5.
> 
> Best,
> Ralf
> 
> Am 19.10.2011 23:43, schrieb Villmow, Micah:
> > Ralf,
> >   What version of the SDK were you using for your analysis? I don't
> see that in the slides/pdf.
> >
> > Thanks,
> > Micah
> >
> >> -----Original Message-----
> >> From: llvmdev-bounces at cs.uiuc.edu [mailto:llvmdev-
> bounces at cs.uiuc.edu]
> >> On Behalf Of Ralf Karrenberg
> >> Sent: Wednesday, October 19, 2011 2:13 PM
> >> To: llvmdev at cs.uiuc.edu
> >> Subject: Re: [LLVMdev] ANN: libclc (OpenCL C library implementation)
> >>
> >> Hi everybody,
> >>
> >> the compiler design lab at Saarland University (chair of Sebastian
> >> Hack)
> >> is also working on an LLVM-based OpenCL driver.
> >>
> >> The project started as a use-case for our "Whole-Function
> >> Vectorization"
> >> library, which allows to transform a function to compute the same as
> W
> >> executions of the original code by using SIMD instructions (W = 4
> for
> >> SSE/AltiVec, 8 for AVX).
> >>
> >> The algorithm, a few details on the OpenCL driver, and some results
> >> were
> >> published at CGO'11:
> >> http://dx.doi.org/10.1109/CGO.2011.5764682
> >>
> >> In contrast to Clover and pocl, we aimed at maximum performance
> before
> >> full support of the API (which simply requires more manpower than
> one
> >> PhD student).
> >> The driver was evaluated using benchmarks from the AMD APP SDK, e.g.
> >> Mandelbrot, NBody, FastWalshTransform, Histogram, BlackScholes, DCT,
> >> ...
> >> Our measurements show that our driver outperforms both Intel's and
> >> AMD's
> >> CPU driver for almost all of the benchmarks.
> >>
> >> We plan to release both the vectorization library as well as the
> OpenCL
> >> driver under a BSD-style license, but there is still significant
> work
> >> to
> >> be done in terms of stability and feature completeness (e.g. the ICD
> >> mechanism only works as expected under Windows).
> >> Also, due to simplicity we currently employ AMD's OpenCL-to-LLVM
> >> frontend and OpenCL-library from an earlier SDK. libclc sounds like
> the
> >> perfect fit for us to get rid of that.
> >>
> >> I agree on the fact that we should try to merge the different
> >> open-source OpenCL projects, but at least at first glance they do
> not
> >> seem to share too many design decisions.
> >>
> >> More information on Whole-Function Vectorization and our driver can
> be
> >> found on the project web page:
> >> http://www.cdl.uni-saarland.de/projects/wfv
> >>
> >> Best regards,
> >> Ralf
> >>
> >>
> >> Am 19.10.2011 17:38, schrieb Hal Finkel:
> >>> Do we have a list of these open-source LLVM-based OpenCL projects
> >>> somewhere? Off the top of my head, we have:
> >>>
> >>> libclc: http://www.pcc.me.uk/~peter/libclc/
> >>> pocl: https://launchpad.net/pocl
> >>> clover: http://cgit.freedesktop.org/~steckdenis/clover/
> >>>
> >>> (I think that all of these have BSD- or MIT-style licenses).
> >>>
> >>> Are there any others?
> >>>
> >>>    -Hal
> >>>
> >>> On Wed, 2011-10-19 at 14:47 +0100, Peter Collingbourne wrote:
> >>>> Hi,
> >>>>
> >>>> This is to announce the availability of libclc, an open source,
> BSD
> >>>> licensed implementation of the library requirements of the OpenCL
> C
> >>>> programming language, as specified by the OpenCL 1.1
> Specification.
> >>>> libclc is intended to be used with Clang's OpenCL frontend.
> >>>>
> >>>> libclc website: http://www.pcc.me.uk/~peter/libclc/
> >>>>
> >>>> libclc is designed to be portable and extensible. To this end,
> >>>> it provides generic implementations of most library requirements,
> >>>> allowing the target to override the generic implementation at the
> >>>> granularity of individual functions.
> >>>>
> >>>> libclc currently only supports the PTX target, but support for
> more
> >>>> targets is welcome.
> >>>>
> >>>> How does this project relate to the recently announced Portable
> >> OpenCL
> >>>> (POCL) project?  Unlike POCL, this project is not intended to
> >> provide
> >>>> an OpenCL host library (i.e. the OpenCL Platform Layer and OpenCL
> >>>> Runtime specified in sections 4-5 of the OpenCL specification).
> >>>> Instead, it provides only the requirements for the OpenCL C
> >>>> Programming Language (section 6 et seq).  It is intended to be
> used
> >>>> with an existing host library implementation, and comply with its
> >>>> ABI requirements.
> >>>>
> >>>> An example of such a host library is NVIDIA's OpenCL host library
> >>>> for PTX -- the intention is to at some point provide a mechanism
> >>>> for using the NVIDIA implementation of OpenCL with Clang, libclc
> >>>> and LLVM's PTX backend instead of NVIDIA's own OpenCL compiler.
> >>>> Another example would be POCL's host library, and the POCL
> >> developers
> >>>> have expressed an interest in using libclc as their OpenCL C
> library
> >>>> instead of developing their own.
> >>>>
> >>>> I will hope to find time over the next few weeks to add libclc
> >> support
> >>>> to the Clang driver.  The intention is that compiling OpenCL C
> >> programs
> >>>> to PTX would be as easy as (something like this):
> >>>>
> >>>> clang -target ptx32 -S file.cl
> >>>>
> >>>> such that the driver would automatically locate the libclc
> headers,
> >>>> add them to the include path and pre-include the main header file.
> >>>> (The libclc support will of course be optional, and a -cl-stdlib=
> >>>> flag will be provided to allow for switching between OpenCL
> standard
> >>>> library implementations.)
> >>>>
> >>>> Thanks,
> >>>
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> >
> >
> >