Zuck's obvious mistake: he should have written the PHP compiler to precompile chunks of GPU code that would be the only code that actually runs when serving web

Zuck's obvious mistake: he should have written the PHP compiler to precompile chunks of GPU code that would be the only code that actually runs when serving web pages. </sarcasm> Facebook isn't really a comparable problems, because ALL of the performance-critical code in PyTorch does runs on a GPU.