Could not find .mm_profdata file

[fpoli]

I'm using for the first time measureme to profile the compilation time of a project which needs to be compiled with nightly-2020-09-30. I followed this guide and I'm getting the following error.

Error: "Could not find profiling data file `prusti_driver-32670.mm_profdata`.It looks like your profiling data has been generated by an out-dated version of measureme (0.7 or older)."

Is it because the measureme version that comes with nightly-2020-09-30 is out-dated? Do you know any workarounds?

[fpoli]

To match the version used by rustc I had to run cargo install specifying a tag:

cargo install --git https://github.com/rust-lang/measureme --tag 0.7.1 crox flamegraph summarize

Maybe it's worth adding this to the guide, mentioning that the tag should match the version of measureme used by rustc.

[kennykerr]

I ran into the same problem after following the instructions here:

https://blog.rust-lang.org/inside-rust/2020/02/25/intro-rustc-self-profile.html

Thanks for the tip!

[wesleywiser]

Just FYI, this is happening because we've made some breaking changes to this crate but rustc hasn't been updated yet to the latest version. We're getting ready to do that now so this should be resolved in the next week hopefully.

[wesleywiser]

Since rust-lang/rust#77398 landed yesterday, this should be resolved.