pop quiz! What does this mean in "real numbers"?
but a x0.82 regression
I presume 18% slower (e.g., from 1 second to 1.18 seconds) but not sure
Or perhaps a 82% slowdown?
It was also phrased as
~ 15% slowdown
Okay, now that's very interesting. The numbers just don't match up, or at least not that I can tell...
I assume that it comes from https://internals.rust-lang.org/t/help-us-benchmark-saturating-float-casts/6231/14
name base ns/iter saturate ns/iter diff ns/iter diff % speedup bench_rgb 34,507,766 42,325,700 7,817,934 22.66% x 0.82
And now I'm angry about "speedup" because it seems like any positive "speedup" should increase the speed.
yeah "speedup" for a measurement where something got slower is ungreat (that's why I wrote "regression" instead) but it's established benchmarking convention to give a ratio where 1.0x is no change and >1.0x is faster. anything with percentages is either misleading or an unconventional presentation of the same ratio
@rkruppe yeah, I'm a big fan of the ratio, but I don't even attempt to use short words. I've never found any that are unambiguous. I always just say something like "is X of the previous time"
"with saturation enabled, the benchmark takes 1.23x of the previous time"
or even more verbose "...the benchmark is slower, taking 1.23..."
@rkruppe yeah "speedup" didnt work out. I read that and had literally no idea what it meant