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Re: advice on reducing C stack frame size?
From: |
Han-Wen Nienhuys |
Subject: |
Re: advice on reducing C stack frame size? |
Date: |
Sat, 13 Sep 2008 15:48:37 -0300 |
User-agent: |
Thunderbird 2.0.0.16 (X11/20080723) |
Andy Wingo escreveu:
> Hi,
>
> With a local patch, it seems that my C stack frames are getting large
> enough to start hitting the stack overflow checks.
>
> (In the future this won't be a terrible problem, as you won't be
> recursively calling the evaluator the the vm then the evaluator etc too
> much, but while we still have a fair amount of code being interpreted,
> it is important.)
>
> So for example, just sitting at the repl, we have:
>
> frame (I think). It is about 20 kilobytes!!! In contrast, a deval frame
> appears to be less, but still excessive:
>
> #19 0x0014b076 in deval (x=0xb7f3a478, env=0xb7ee2560) at eval.i.c:358
> 358 (void) EVAL (form, env);
> (gdb)
> #20 0x0014e72e in scm_dapply (proc=0xb7f3a6d0, arg1=<value optimized
> out>, args=0xb7ee25d0) at eval.i.c:1858
> 1858 RETURN (EVALCAR (proc, args));
> (gdb) p 0x0014e72e - 0x0014b076
> $5 = 14008
>
> This is with gcc 4.3.0 20080428 (Red Hat 4.3.0-8).
>
> My question is: what should I do about this? Wait for the runtime tuning
> patches to land in master and then merge them? Assume that over time, I
This looks like a bug or an oversight. - 14k is about 3500 SCM values; we
surely
don't have that many local variables, so it looks as if there might be some
macro that expands into a local array. I'd have a look at the addresses of
the
different local variables to see where all that memory is going. Also, look at
the preprocessed source and scan for array variables.
--
Han-Wen Nienhuys - address@hidden - http://www.xs4all.nl/~hanwen