[PATCH] D115138: [llvm-mca] Compare multiple files

[Andrea Di Biagio via Phabricator via llvm-commits]

andreadb added a comment.

It would be very useful if we could also pass extra flags in input to llvm-mca.
As you know, flags like `-noalias` and/or `-dispatch` may affect the outcome of a simulation. When doing a diff, users should be allowed to pass extra args to llvm-mca.

This also leads to a (minor) issue with the output of this script.
The simulation setup is currently not printed out. The only context that we get is:

- which files were passed in input to the script
- the total number of iterations.

That information may not be enough to reproduce an experiment. For example, you would need to know what the other flags were (example: which subtarget was specified).

I think that we should print out which flags were actually passed in input to llvm-mca. If people are concerned about the verbosity of it, then we can do it only the user has asked for a more verbose output (e.g. flag -v (verbose) was passed in input to the script).

Last: have you considered also diffing .json files? I guess that the feature of diffing json files could be added in future. It would allow skipping the first step (i.e. the actual simulation step), and it would simply compare the .json outputs if compatible (i.e. target settings are the same). This is just an idea. In case, it could be contributed in future as a follow-up patch if we think it would be useful.

I hope it makes sense.


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  https://reviews.llvm.org/D115138/new/

https://reviews.llvm.org/D115138