Indeed, max bytecode count (FreqInlineSize and MaxInlineSize) and inlining depth (MaxInlineLevel). Your GC choice will also slightly modify the inlining decisions, and then obviously GraalVM will be completely different.
Is there a full list of the differences between the graal jit and C2? I was only aware of graal having better partial escape analysis over C2's conservative EA.
It's simply a completely different implementation. Some of the optimiization passes are the same, obviously, but overall it simply performs ... differently.
Correct! Inlining obviously costs CPU, code cache space, and makes the receiver method bigger so that it's less likely it will be inlined itself. If there ever is a decompilation occuring, the inlining efforts were pretty much wasted.