Re: [ANN] LuaJIT-2.0.0-beta1

[Mike Pall <mikelu-0911@...>]

Alexander Gladysh wrote:
> I'm interested in the profiler.
> 
> Does not have enough information on whether it would justify to be a
> commercial tool, but it surely looks like a tool I'd like to use when
> I'm tuning performance of Lua code for LJ2.

The raw information is already there. Sampling it fast enough with
minimal overhead is a bit tricky, but I mostly solved that. The
real challenge is to make a nice GUI around it (like Shark) and to
package it and market it and sell it ... gaah, no fun.

Here's the visualization of SciMark:
  http://luajit.org/temp/vmprof_scimark.png

[Zoom in with an image viewer, not with a browser.]

Of course it's all green, because it compiles well. The little
blue/red blotches are where the JIT compiler jumps in (i.e. very
low overhead). The five phases (different sub-benchmarks) are
clearly visible and it's easy to see how branchy they are.

One could make a tool where you move over it with a mouse and it
pinpoints the source location in a window next to it. But I don't
like writing GUIs (anymore). Someone up to it?

--Mike