[LLVMdev] Would DosBox benefit from LLVM JIT?

[Jacek Wielemborek]

W dniu 22.07.2015 o 15:21, David Chisnall pisze:
> A sequence of 32 instruction is not very likely to have many
> optimisation opportunities that LLVM can take advantage of. 

I don't know the codebase, but perhaps it's as easy as increasing the
number here and maybe adjusting some relevant buffers:

https://github.com/wjp/dosbox/blob/idados/src/cpu/core_dynrec.cpp#L212

> You may
> get a speedup from longer traces, though of course the LLVM JITing
> time is likely to be longer, so you’d want to make sure that it’s
> done in a separate thread.  If you can get longer traces (and DOSBox
> has the infrastructure already for invalidating on self-modifying
> code) then you may be able to get some speedup.

Introducing another thread sounds like a difficult task, though it
definitely makes sense and could be worth it, though...

> There was a similar project to use LLVM in QEMU a few years ago that
> failed to provide a speedup.
> 
> David

Why did it fail?

-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 819 bytes
Desc: OpenPGP digital signature
URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20150722/177b8c38/attachment.sig>