>> Proebsting's Law: Compiler Advances Double Computing Power Every 18 Years
>> I claim the following simple experiment supports this depressing claim. Run your favorite >> set of benchmarks with your favorite state-of-the-art optimizing compiler. Run the
>> benchmarks both with and without optimizations enabled. The ratio of of those numbers
>> represents the entirety of the contribution of compiler optimizations to speeding up
>> those benchmarks. Let's assume that this ratio is about 4X for typical real-world
>> applications, and let's further assume that compiler optimization work has been going on >> for about 36 years. These assumptions lead to the conclusion that compiler optimization >> advances double computing power every 18 years. QED.
>>
>> This means that while hardware computing horsepower increases at roughly 60%/year,
>> compiler optimizations contribute only 4%. Basically, compiler optimization work makes
>> only marginal contributions.
???
So what kind of optimisation are we talking about ?
1. Microoptimisations - well modern GHz micros are pretty fast at everything - they'll even run bad code fast ultimately reducing the ratio difference.
2. Modern Out of order optimisations, superscalar - well these usually do make a more noticeable impact. The DEC Gem Compilers ran code 40% faster - but the compiler is
designed to utilise such architectures on purpose and as such does not have a "only
run this code utilising half the hardware resources of the micro" type mode so a naive
user running a benchmark cannot see the difference.
3. Autoparellelisation detection for the Cells 8 Vector Units - a special case of (2)
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>> Proebsting's Law: Compiler Advances Double Computing Power Every 18 Years >> I claim the following simple experiment supports this depressing claim. Run your favorite >> set of benchmarks with your favorite state-of-the-art optimizing compiler. Run the >> benchmarks both with and without optimizations enabled. The ratio of of those numbers >> represents the entirety of the contribution of compiler optimizations to speeding up >> those benchmarks. Let's assume that this ratio is about 4X for typical real-world >> applications, and let's further assume that compiler optimization work has been going on >> for about 36 years. These assumptions lead to the conclusion that compiler optimization >> advances double computing power every 18 years. QED. >> >> This means that while hardware computing horsepower increases at roughly 60%/year, >> compiler optimizations contribute only 4%. Basically, compiler optimization work makes >> only marginal contributions. ??? So what kind of optimisation are we talking about ? 1. Microoptimisations - well modern GHz micros are pretty fast at everything - they'll even run bad code fast ultimately reducing the ratio difference. 2. Modern Out of order optimisations, superscalar - well these usually do make a more noticeable impact. The DEC Gem Compilers ran code 40% faster - but the compiler is designed to utilise such architectures on purpose and as such does not have a "only run this code utilising half the hardware resources of the micro" type mode so a naive user running a benchmark cannot see the difference. 3. Autoparellelisation detection for the Cells 8 Vector Units - a special case of (2) ------- members.lycos.co.uk/dmoore0100.