3 ms·
A bit off topic, but do we have a standard way to talk about performance improvements in terms of percents? This went from 131 to 76. The 70% calculation was
by rileymat2 11y ago
A bit off topic, but do we have a standard way to talk about performance improvements in terms of percents?
This went from 131 to 76. The 70% calculation was (start-end)/end. Is this the standard method, because it seems like you would divide by the start timing.
- ant6n 11y agoI find reporting like this the wrong way around. It should be a factor requiring no addition and subtraction, like 1.7x faster. Similar with compression. If a 8kb file becomes 2kb, the compression factor should be 0.25x.
- greggyb 11y agoThis might be pedantic, and I'm sorry, but this is something I always wonder about when I talk about performance. When we say 1.7x faster, what is a fast? How does fastness increase? It's nearly 2 fasts instead of one? I think the compression sample you gave is much better. Multiply the original file size by the factor to get the new, compressed file size. This is much better than a statistic that I hear a lot about the compression in a columnstore database we use, where everyone says "7-10x compression", because that was published first and is popular. I'd prefer to see something like your compression example. It took 8 seconds before, and now takes 2. My optimization makes the operation take .25x the time.
- over 11y ago1.7x faster means oldRunningTime / newRunningTime = 1.7. Or in your example, 8 seconds / 2 seconds = 4x faster. Sometimes this is called a speedup of 4x or a 4x speedup.
- greggyb 11y agoI totally get how the math works. I don't like the language. We're not measuring speed or velocity which can be represented as rates. We're measuring time. Speed would be something like operations per second. We're just measuring seconds.
- WillAbides 11y agoThis calculation makes sense if you compare it to miles per hour or iops. If a car went from 20mph to 30mph you would say its speed increases by 50%. Likewise, using 131ns to 76ns, this went from 7,633 per millisecond to 12,157 per millisecond which is about 72% faster. The one that bothers me is when people say something got x percent slower.
- rileymat2 11y agoI guess, but I think my problem is I think of like losing money. Sort of like losing the amount of time it takes. If I went from $100 to $50. I would say I lost 50% of my money. Part of me feels like a 50% performance increase is another way to say that I lost 50% of the time it once took. This is all subjective on my part.
- richard_todd 11y agoI noticed that too. People get it wrong all the time but the right way to discuss a change relative to the starting value is to divide by the starting value.