gnulib: cond & spinlocks

[Sam Steingold]

Bruno,
would it be possible to make gnulib cond allocate on stack?
would it be possible to use fast clisp spinlocks in gnulib lock?
Thanks.

Vladimir Tzankov wrote:
> On Nov 17, 2008, at 9:28 PM, Sam Steingold wrote:
> > I plan to create the thread2 branch after I switch to gnulib
> > threadlib/lock/cond to get solaris and win32 "for free".
>
> Not real objections - but few concerns.
>
> The xmutex_t should be recursive (for consistency - critical section  
> on Win32 are recursive - and gnulib uses them as well).
>
> The cond implementation in gnulib uses malloc() while the current  
> clisp implementation uses the stack. In a long running process this  
> may cause unexpected behavior. Also this is especially true for  
> SPVW_PURE - where the malloc-ed areas can easily mix with the lisp  
> heap (looks to me).
>
> I just looked on the gnulib and do not see "realy fast" spinlocks  
> (may be I am wrong - have not looked too hard). In the current clisp  
> spinlocks are inlined assembly instructions. Every heap allocation is  
> guarded with a spinlock - so any overhead may cause significant  
> decrease in performance.


SAm.