Author: steve-myers
Posted: Thu Feb 09, 2017 1:25 am (GMT 5.5)
Those fractions of seconds do add up. And, surprise, surprise, they're only noticed on mainframes. On toy and baby machines, no one attempts to measure this kind of stuff, so no one cares because it can't be measured. This is one reason projects tend to gas out more often on toy and baby machines because no one checks this in advance. Measurement tools, though they are disappointing in their repeatability, have been in mainframes for decades, though the discipline to actually use them seems to have disappeared, probably because it is not in CS curricula (because it can't be done on toy and baby machines. These guys seem to depend on Moore's "law" to cover up their lapses.
The raw outer shell in my QSORT isn't all that great. Actually, I stole it from K & R, where it was simplified for demonstration purposes. But I can partly make up for it by being efficient in other places, like the compare function.
What I was trying to demonstrate is YOU HAVE TO NOTICE THE SMALL STUFF. ST 14 is a lot faster than STM 14,2. L 14 is much faster then L 14/LM 0,2. You will see a difference if you call the compare function 100,000 times.
Posted: Thu Feb 09, 2017 1:25 am (GMT 5.5)
Those fractions of seconds do add up. And, surprise, surprise, they're only noticed on mainframes. On toy and baby machines, no one attempts to measure this kind of stuff, so no one cares because it can't be measured. This is one reason projects tend to gas out more often on toy and baby machines because no one checks this in advance. Measurement tools, though they are disappointing in their repeatability, have been in mainframes for decades, though the discipline to actually use them seems to have disappeared, probably because it is not in CS curricula (because it can't be done on toy and baby machines. These guys seem to depend on Moore's "law" to cover up their lapses.
The raw outer shell in my QSORT isn't all that great. Actually, I stole it from K & R, where it was simplified for demonstration purposes. But I can partly make up for it by being efficient in other places, like the compare function.
What I was trying to demonstrate is YOU HAVE TO NOTICE THE SMALL STUFF. ST 14 is a lot faster than STM 14,2. L 14 is much faster then L 14/LM 0,2. You will see a difference if you call the compare function 100,000 times.