I am writing about algorithms in a paper and I wonder how to best express increasing the speed of an algorithm. Is it clear when I write "The performance increased by doing X" or can this be ambigious, as performance can also be measured in the quality of the output?
"The algorithm has been sped up" sounds somehow strange and informal to me but I'm not a native speaker.

P.S.: If the algorithm is both faster and the output has a higher quality, can I write "The performance has been increased both qualitatively and quantitatively" or is it not clear that quantitatively relates to the speed? How to rephrase that?