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Comment by ltbarcly3 | Hacker News Reader

Misleading title, it's 90% of the faster time. It's about 45% faster.

It's actually a little bit interesting, if you are interested in how we use language. You could argue that now you now get 90% more work done in the same amount of time, and that would align with other 'speed' units that we commonly use (miles per hour, words per minute, bits per second). However, the convention in computer performance is to measure time for a fixed amount of work. I would guess that this is because generally we have a fixed amount of work and what might vary is how long we wait for it (and that is absolutely true in the case of this blog post) so we put time in the numerator.

It's a very interesting post and very well done, but it's not 90% faster.

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More misleading is that it implies that all packages can be made 90% faster. This is one particular package.

I feel like using units of rate (90% faster) and not units of time makes more sense here.

Plus, if you were using units of time, you wouldn’t use the word “faster.” “Takes 45% less time” and “45% faster” are very different assertions, but they both have meaning, both in programming and outside it.

It comes down to convention. When talking about proportional differences, we can fix the unitary example to be the smaller, larger, earlier, or later, object or subject.

I think, generally, we fix on the earlier when talking about the change over time of a characteristic. "This stock went up 100%, this stock went down 50%". In both cases it's the earlier measurement that is taken as the unit. That makes this a 45% reduction in time to do the work, and that's actually what they measured.

When talking about comparisons between two things that aren't time dependent it depends on if we talk in multiples or percents I think. A twin bed is half as big as a king bed. A king bed is twice as big as a twin bed. Both are idiomatic. A king bed is 100% bigger than a twin bed. Yes, you could talk like this. A twin bed is 100% smaller than a king bed. Right away you say wait, a twin bed isn't 0 size! Because we don't talk in terms of the smaller thing when talking about decreasing percents, only increasing. A twin bed is 50% smaller than a king bed (iffy). A twin bed is 50% as big as a king bed. There, that's idiomatic again.

Great read. I hadn't even considered that people might interpret "90% faster" as "10 times as fast", i.e., it will take 100-90=10% of the original time. It seems like a completely incorrect interpretation to me, but obviously there are people who read it with this understanding. Huh.

It is unfortunate (because how do you interpret 100% faster) but a common interpretation of X% faster implies it takes x% less time than before. One easy way is to have chatgpt give a numeric example for a statement like this, and in all cases I tried it gives an example of sorts if the job took 100 seconds before it takes 10 seconds now (a 10x increase), and I'm assuming it is a representation of common usage based on how much data is used to train it.

After thinking about it more, I think I know why it seems misleading. They are talking about the change in the larger value as a % of the smaller value. That's what is misleading. They are saying it is reduced by 90% (of some other thing). When you say "We reduced THING by N%" it's just assumed that the N% is N% of THING, not OTHER THING.

I think you're right. I think you could say the package (as in the code) is 45% faster or that the package increases parsing rate by 90%. But mixing the two is confusing.

I think it's an interpretation issue. When you say it's 45% faster I interpret that as "the new package handles work at a rate of 145% when compared to the original, that is, 1.45 times as fast".

I would rephrase your comment as "the package takes 45% less time to process a given data set".

Thanks for this, as an average HN user I didn't click the link and just skimmed the comments thinking how is it possible that they reduced the runtime to 10% of the original. This post clarifies that for me (now on to actually read the blog post).

The title doesn’t imply that at all though. 100% faster means doubled speed. 10% runtime means 1000% faster.

I think it's not idiomatic to talk that way, especially because it's ambiguous.

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