rts: eras profiling mode
The eras profiling mode is useful for tracking the life-time of closures. When a closure is written, the current era is recorded in the profiling header. This records the era in which the closure was created.
- Enable with -he
- User mode: Use functions in GHC.Profiling.Eras to modify the era
- Automatically: --automatic-era-increment, increases the user era on major collections
- The first era is era 1
- -he can be used with other profiling modes to select a specific era
If you just want to record the era but not to perform heap profiling you
can use -he --no-automatic-heap-samples
.
Fixes #24332 (closed)