Re: Random crashes with ABC enabled
- From: Denis Golovan <denis.golovan@xxxxxxxxx>
- To: luajit@xxxxxxxxxxxxx
- Date: Thu, 27 Mar 2014 20:41:47 +0200
2014-03-27 13:05 GMT+02:00 Mike Pall <mike-1403@xxxxxxxxxx>:
> I wonder whether your problems couldn't be solved better by
> working around these issues in your code. E.g. using branch-free
> idioms, manually unrolling loops with a low iteration count or
> on-the-fly code generation from templates.
Yes. I see what you mean.
That said I can't go that way.
The idea of implementing this specific number crunching algorithms was
in creating a really small amount of core APL-like vector
functions/operations (plus something similar to multiple dispatch in
CL) and implementing some other performance critical code in
traditional C-like style.
A smallish APL-like core is necessary for building quick prototypes
and only if some optimization is required I go back C-style route.
That idea worked really well so far. LuaJIT did wonders in unrolling
deeply nested "generic" functions and building specific C-style code
in small tight loops.
>> jit.opt.start("-abc") -- without this one if happens really often
>
> Well, FFI accesses are not bounds-checked, anyway. So disabling
> ABC elimination does nothing for those loops. The problem must be
> somewhere else.
That makes sense, of course. Looks like I need to retest my assumptions again.
> That said: out-of-bounds FFI write accesses and unanchored FFI
> cdata objects are very common causes for intermittent crashes and
> various strange symptoms. You should double-check the code for
> that. If the problems cease when you use collectgarbage("stop")
> then you most certainly have an unanchored FFI cdata object.
Hm.
Could you confirm that by "unanchored FFI cdata" you mean native
arrays which are deallocated randomly by non-Lua part?
BR,
Denis
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