On Fri, 17 Jan 2025, Matthew Pickering wrote:
1. As Zubin points out we have recently been concerned with improving the memory usage of large module sessions (#25511, !13675, !13593)
I imagine all these patches will greatly help the memory usage in your use case.
I'll try these out and report back.
2. You are absolutely right that ModDetails can get forced and is never reset.
If you try !13675, it should be much more easily possible to reset the ModDetails by writing into the IORef which stores each home package.
Yes, that makes sense.
3. If you share your example or perhaps even a trace from ghc-debug then I will be happy to investigate further as it seems like a great test case for the work we have recently been doing.
Untangling just the parts that exercise the GHC API from all the other in-house bits will be quite a lot of work. But if just a ghc-debug snapshot of e.g. a small example from scratch vs. from existing ModIfaces would be helpful (with e.g. the top HscEnv at the time of finishing all typechecking as a saved closure), I can provide that no prob. Thanks, Gergo