[cfe-dev] parallel C++

[Edward Givelberg via cfe-dev]

Jeff,
Multi-core CPUs and all the associated software technologies (shared
memory, threads, etc) are a technological dead end.
I argue more than that: all software technologies that use processes
are dead on arrival. This includes the technologies you mention in
your presentation
https://www.ixpug.org/images/docs/KAUST_Workshop_2018/IXPUG_Invited2_Hammond.pdf
People got used to processes over decades, so when they talk about
parallelism they immediately talk about processes, but this is the root of
the problem. I propose object-level parallelism. An object is more than a
process. It is a virtual machine.

I propose to introduce remote pointers into C++. I am very surprised nobody
thought of this before. I'd be curious to know how much work
people think this would be to do it in LLVM. I know it may be possible to
introduce something like remote_ptr, but I don't think it is a good idea.

I am also proposing a new way of executing code, which I call causal
asynchronous execution. I'd like to know if people find it natural to write
code like this.








On Mon, Nov 26, 2018 at 10:26 PM Jeff Hammond <jeff.science at gmail.com>
wrote:

> I’ll probably have more detailed comments later but the related work you
> may wish to consider includes:
> - UPC and Berkeley UPC++
> - Charm++
> - HPX from LSU
> - DASH (http://www.dash-project.org/)
> - MADNESS (https://arxiv.org/abs/1507.01888)
>
> There are quite a few dead parallel C++ dialects from the last millennium
> but it’s probably not worth your time to find and read about them.
>
> I’m very glad that you used MPI as your communication runtime. This will
> save you lots of pain.
>
> Jeff
>
> On Mon, Nov 26, 2018 at 2:57 PM Edward Givelberg via cfe-dev <
> cfe-dev at lists.llvm.org> wrote:
>
>>
>> Chris Lattner suggested that I post to this mailing list.
>>
>> I used Clang/LLVM to build a prototype for parallel
>> interpretation of C++. It's based on the idea that C++
>> objects can be constructed remotely, and accessed via
>> remote pointers, without changing the C++ syntax.
>> I am a mathematician, not an expert on compilers.
>> I am proposing changes to the C++ standard and to the
>> compiler architecture, so I'm very interested to hear from
>> experts.
>> My paper is
>> https://arxiv.org/abs/1811.09303
>> Best regards,
>> Ed
>>
>> -----------------------------------------------------------------
>> A solution to the problem of parallel programming
>> E. Givelberg
>>
>> The problem of parallel programming is the most important
>> open problem of computer engineering.
>> We show that object-oriented languages, such as C++,
>> can be interpreted as parallel programming languages,
>> and standard sequential programs can be parallelized automatically.
>> Parallel C++ code is typically more than ten times shorter than
>> the equivalent C++ code with MPI.
>> The large reduction in the number of lines of code in parallel C++
>> is primarily due to the fact that communications instructions,
>> including packing and unpacking of messages, are automatically
>> generated in the implementation of object operations.
>> We believe that implementation and standardization of parallel
>> object-oriented languages will drastically reduce the cost of
>> parallel programming.
>> his work provides the foundation for building a new computer
>> architecture, the multiprocessor computer, including
>> an object-oriented operating system and more energy-efficient,
>> and easily programmable, parallel hardware architecture.
>> The key software component of this architecture is a compiler
>> for object-oriented languages.  We describe a novel compiler
>> architecture with a dedicated back end for the interconnect fabric,
>> making the network a part of a multiprocessor computer,
>> rather than a collection of pipes between processor nodes.
>> Such a compiler exposes the network hardware features
>> to the application, analyzes its network utilization, optimizes the
>> application as a whole, and generates the code for the
>> interconnect fabric and for the processors.
>> Since the information technology sector's electric power consumption
>> is very high, and rising rapidly, implementation and widespread
>> adoption of multiprocessor computer architecture
>> will significantly reduce the world's energy consumption.
>> _______________________________________________
>> cfe-dev mailing list
>> cfe-dev at lists.llvm.org
>> http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-dev
>>
> --
> Jeff Hammond
> jeff.science at gmail.com
> http://jeffhammond.github.io/
>
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