Re: optimizing compilers for low power design

On 6/15/2014 10:43 AM, Kaz Kylheku wrote:
> On 2014-06-15, idatarm@gmail.com <idatarm@gmail.com> wrote:
>> Abstract: We describe an algorithm for optimizing compilers for low
>> power design. The algorithm can be applied to almost any c compiler
>> and in particular we target gcc compiler. The algorithm works by
>> modifying optimization table lookup of gcc. This works in theory. We
>
> Instructions do not have a fixed power cost which can be measured by
> repeating a long run of that instruction and then dividing.
> It depends on their operands, and the complex state of the CPU (what
> other instructions are in the pipeline before and after, caching, etc).
> This approach might work on a very old processor, on which every instruction
> had a predictable instruction count.


I see it as plausible that different functional units can take
usefully different power to compute (i.e., using x86 SSE instructions
versus the x87 instruction set, or using vectorized versus
non-vectorized instructions). Even then, though, I consider it only an
a priori plausible event--you'd need to provide experimental evidence
that it actually occurs in practice before continuing.


> Percentages do not add.


Were that the only serious error of this paper. The percentages
themselves seem to be literally conjured out of thin air.


> Your paper's reference [1], "A Guide to LaTeX" is inappropriate to your
> topic and suggests that you're trying to inflate your reference section. If
> you're going to do this this, bury the questionable reference in the
> middle of the list; do not begin the list with one.


The other 4 references are equally irrelevant. Two of them are
self-citations of earlier work on what appears to be waveform pattern
generation for electrical circuits and the other two may be culled from
the references of those problems. In contrast, a typical PL paper would
contain a page of references or more.


> You have a typographical problem.


The grammatical mistakes in the paper reached the threshold of "actively
distracting" for me.


Curious, I decided to see what other papers might be found, given that
the URL contains a papers folder.
...


Unfortunately, this appears to be the most logically cohesive paper of
the lot. The more I read, the more I got the feeling that the author is
very much outside of his capabilities in this line of work.


--
Beware of bugs in the above code; I have only proved it correct, not
tried it. -- Donald E. Knuth

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