Rakudo needs better performance from Parrot, and Parrot can provide it.  Here are several areas of exploration.

||'''In progress?'''||'''Explanation'''||'''Difficulty'''||'''Amount of Work'''||'''Benefit Estimate'''||
||*|| [wiki:FixingConstantSTRINGCaching] ||moderate||low||big memory savings, 3% performance improvement, further benefits from other string changes (avl_string_cache branch)||
||*||[wiki:RemoveUnnecessaryDataFromConfig]_lib.pbc||low||low to moderate||5-10% Parrot startup (2.926% achieved with r45623, more possibilities await)||
|| ||String equality macro||low||low||2-3%||
|| ||Slim parrot_string_t||low||low to moderate||2-3%, depending on workload||
|| ||Make fast core the default core||low to moderate||low||2-3%||
|| || [wiki:FixingPIRVtableOverrides] ||moderate||low to moderate|| 5%||
|| ||Fix freeze/thaw of complex PMCs||difficult||moderate to high||huge startup improvement for Rakudo||
|| ||Implement sweep-free GC||moderate to high||moderate||10%, depending on workload||
|| ||Remove PMCProxy||high||moderate||5-7%||
|| ||Implement garbage-first GC||high||high||10-15%||
|| ||Type-specific hashes||low to moderate||low to moderate||3-5%||
|| ||Store CallSignatures in PBC||moderate||low to moderate||7-8%||
|| ||Cheaper access to object attributes||moderate to high||moderate||5-7%||
|| ||Lorito||high||high||orders of magnitude||

Completed tasks:

|| ||Remove PMC struct's sync||low||low||2% at most (done in rr46289)||