[HN Gopher] Zebras hate you for no reason: Why Amdahl's law is m...
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Zebras hate you for no reason: Why Amdahl's law is misleading
(2017)
Author : jacquesm
Score : 29 points
Date : 2022-12-02 12:44 UTC (1 days ago)
(HTM) web link (www.embeddedrelated.com)
(TXT) w3m dump (www.embeddedrelated.com)
| bombcar wrote:
| Kittensgame! Stay away!
|
| Paperclips have nothing on it. I warn you!
|
| Now let me go reset, I think this time with a Challenge ...
|
| As to the article, it's a good point - optimizing something can
| provide more benefits than it seems at first, especially over
| time.
| MrMetlHed wrote:
| God I just heard of this game a month ago and it's like crack.
| I prefer Universal Paperclips because it had a nicely defined
| ending and more interesting phases, but Kittens Game is a nice
| diversion from the usual mobile fare. And a single purchase.
| FumblingBear wrote:
| I'd like to think I have some level of willpower and self
| control, but incremental games like Kittens Game are my
| kryptonite. There's something so compelling to me about seeing
| the numbers go up and I don't even fully understand why.
|
| If you enjoy that type of game, I highly recommend Kittens Game
| as the pinnacle of the genre--especially since it doesn't feature
| any microtransactions or dark patterns, but be warned: it can be
| incredibly addicting.
| yodon wrote:
| So many great observations buried in so many needlessly wordy
| examples.
| artemonster wrote:
| What were those "great observations"?
| TechnicolorByte wrote:
| I'd love a summary, too. Started reading the first third but
| got bogged down by all the Kitten Game examples.
|
| I think the conclusion at the bottom captures most of it.
| bstpierre wrote:
| Amdahl's law says we're only going to get marginal
| improvements in a lot of cases. But that's ok because
| sometimes marginal improvements still pay off.
|
| Increasing efficiency doesn't always mean shorter runtime,
| sometimes it means more production from an equal runtime.
|
| Lots of improvements to different places in the pipeline can
| pay off.
|
| Sometimes an improvement in one part of the process can have
| synergistic knock-on effects in other, perhaps unexpected,
| parts of the larger system. It seems like these can be hard
| to predict without taking a deep look at the larger system
| and how all of its component parts interact.
| artemonster wrote:
| thank you for the summary!
| bstpierre wrote:
| At least twice during my career I've had to shrink some
| binary output so it can fit onto a fixed size part in some
| embedded system.
|
| Once it was a FTTX CPE, and it needed to ship but the
| binary was a couple KB too big. The programmer on the
| project found a little bit of savings but not enough. I
| looked at the code, looked at the assembly output, and
| found a spot where a switch/case was being transformed into
| a huge jump table that was mostly sparse. (The embedded
| toolchain compiler wasn't great at optimization.) A little
| refactor to this one function was enough savings to be just
| under the limit for whatever chip they were using. (I feel
| bad for the next person who has to fix a bug in that
| product.)
|
| The relevant aspect to my story is that sometimes an
| improvement in one area can make another area worse! But
| that's ok, because even though my function rewrite was
| almost certainly slower, we had cpu cycles to spare but not
| enough storage.
| mcphage wrote:
| Gustafson's Law reminds me of Jevon's Paradox:
| https://en.m.wikipedia.org/wiki/Jevons_paradox
|
| ...namely, that every time we get more efficient at using energy,
| we increase the amount we produce of it. Instead of doing the
| same things with less energy, instead we are now able to do new
| things that were cost prohibitive previously.
| retrac wrote:
| An example: artificial lighting. Despite most lighting
| transitioning to fluorescent then LED, total electric demand
| used for lighting hasn't really gone down as the cost has gone
| down; people just floodlight everything now. Some napkin math
| indicates Canadians use about ~10x as much artificial light per
| capita compared to 50 years ago.
|
| It's not a law, of course, or at least not a simple one. E.g.,
| the cost to refrigerate has come down similarly, but while air
| conditioning continues to increase in use, average
| freezer/fridge space plateaued in the 1980s. Everyone seems to
| now have as much freezer space as they want. Some demands are
| fully satisfiable and people don't necessarily consume more,
| even as the cost comes down.
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