> I agree that it would be nice to have the same mechanism for all. > > The main hurdle I see is how to allow for concurrent code generation while > minimizing flushes of the single, fixed-size[*] code_gen_buffer. > In user-mode this is tricky because there is no way to bound the number > of threads that might be spawned by the guest code (I don't think reading > /proc/sys/kernel/threads-max is a viable solution here). > > Switching to a "__thread *tcg_ctx_ptr" model will help minimize > user-mode/softmmu differences though. The only remaining difference would be > that user-mode would need tb_lock() around tb_gen_code, whereas softmmu > wouldn't, but everything else would be the same.
Hmm, tb_gen_code is already protected by mmap_lock in linux-user, so you wouldn't get any parallelism. On the other hand, you could just say that the fixed-size code_gen_buffer is protected by mmap_lock, which doesn't exist for softmmu. Paolo
