3 ms·
We really don't know what causes perf differences, layout has more of an effect than -O1 to -O3. "Performance Matters" by Emery Berger https://www.youtube.com/
by nerpderp82 4y ago
We really don't know what causes perf differences, layout has more of an effect than -O1 to -O3.
"Performance Matters" by Emery Berger
https://www.youtube.com/watch?v=r-TLSBdHe1A https://www.youtube.com/watch?v=r-TLSBdHe1A
- tmtvl 4y agoI wonder if he mentions running from a different directory and running as a different user to highlight how annoying the effect from the environment is, as USER and PWD are part of the environment.
- josephg 4y agoIf thats true, it seems like you could make a great optimization pass which chooses a code layout in order to make the program run faster. I wonder how predictable code layout is on performance across different CPUs. Sounds like an interesting problem!
- nerpderp82 4y agoTotally agree, area is ripe for a lot of experimentation and data visualization. I think it would be fun to see what is the minimal amount of insertions or shifts in layout to get the most pathological decrease in performance. Could be a great vehicle to challenge performance assumptions we all have.