http://qs1969.pair.com?node_id=681160


in reply to Re^2: CPU cycles DO NOT MATTER! (EXPLETIVE!)
in thread CPU cycles DO NOT MATTER!

Right now, in Perl, CPU cycles almost always do not matter.

In 1973, oil prices jumped from ~$3/barrel to $12/barrel. The worlds economy went into a downward spiral that would lasted ~7 years. Inflation was rampant throughout the world. Unemployment went through the roof in most Western Economies. Food prices rose at unprecedented rates.

In 1980, oil prices jumped from $15/barrel to $40/barrel. The world's economies went into downward sprials.

But still the world car industry, especially in the US, kept churning out 5 litre "shopping cars" return ~10 mpg. Imagine the savings in raw oil stocks if the lessons had been heeded and no new cars were produced from 1974 onwards, that used say, < 40mpg? How many billions of barrels of oil would that have saved?

Today, oil prices have recently peaked at $115/barrel. The price of rice, wheat and other basic foodstuffs has tripled in some places. Bread, milk, rice and all the foodstuffs produced from them, including meat, are rising weekly--some daily. The worlds banks are suffering meltdown due to bad deptsdebts. Inflation is threatening. Unemployment rising.

Some figures put the energy used by commercial computer and related equipment as 13% of the total energy consumption world wide. Wasted cycles == wasted energy. Both in the direct energy usage, and the indirect cost of dealing with the heat generated. Throwing hardware at performance problems without considering the possibility of optimisations (either better algorithms or better code), is exactly the same as building low-efficiency gas-guzzling car engines because they are, in the short term, "cheaper" to produce.

The lessons of history are free to learn for those that will.


Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
"Science is about questioning the status quo. Questioning authority".
In the absence of evidence, opinion is indistinguishable from prejudice.

Replies are listed 'Best First'.
Re^4: CPU cycles DO NOT MATTER! (EXPLETIVE!)
by radiantmatrix (Parson) on Apr 21, 2008 at 16:17 UTC

    The worlds banks are suffering meltdown due to bad depts.

    I know that "depts." is a typo, but it's such a wonderful one because of its surprising truth.

    <radiant.matrix>
    Ramblings and references
    The Code that can be seen is not the true Code
    I haven't found a problem yet that can't be solved by a well-placed trebuchet
Re^4: CPU cycles DO NOT MATTER! (EXPLETIVE!)
by dragonchild (Archbishop) on Apr 17, 2008 at 17:47 UTC
    And when power prices make it more economical to optimize vs. throw hardware at it is when it will become cost-efficient to do so. Until then, the business loses money if it optimizes at every turn. As businesses only exist to make money, a money-losing business doesn't stay in business.

    My criteria for good software:
    1. Does it work?
    2. Can someone else come in, make a change, and be reasonably certain no bugs were introduced?
      As businesses only exist to make money, a money-losing business doesn't stay in business.

      In the 70s, it was cheaper to use iron instead of aluminium for engine blocks. And cheaper to throw CCs at the resultant weight than to make the engines more fuel efficient. But then, oil was $3/barrel, now $115/barrel.

      Have you heard the expression. Costs the earth?

      My machine is currently generating a 250M element dataset. My first attempt would have run for 57 days. I abandoned it. My second attempt would have run for 4 days. A couple of optimisations and I got that down to 20 hours. Total time expenditure was maybe 6 hours.

      Or I could have bought 70 machines, plus clustering software with shared memory capability. You do the math.


      Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
      "Science is about questioning the status quo. Questioning authority".
      In the absence of evidence, opinion is indistinguishable from prejudice.