Last I looked AutoFDO builds were similar in performance to PGO as ThinLTO vs LTO is. I’d say that collecting data with an instrumented Chrome build is extremely difficult - you’re relying on your synthetic benchmark environment which is very very different from the real world (eg extensions aren’t installed, the patterns of websites being browsed is not realistic, etc). There’s also a 2x compile cost because you have to build Chrome twice in the exact same way + you have to run a synthetic benchmark on each build to generate the trace.
I’m just using an educated guess to say that at some point in the future Chrome will switch to AutoFDO, potentially using traces harvested from end user computers (potentially just from their employees even to avoid privacy complaints).
I’m just using an educated guess to say that at some point in the future Chrome will switch to AutoFDO, potentially using traces harvested from end user computers (potentially just from their employees even to avoid privacy complaints).