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Re: [Xen-devel] [PATCH] domain.c idle_loop declaration (take 2)



Some further analysis, with much help from Jimmy Xenidis of IBM
research, shows that the problem was not the declaration of the function
as static void, but that the compiler is optimizing the function out of
the assembled code.

The compiler is probably correct in optimizing out the function. It is only called through inline assembly, and it is static void. Further experiments with -02 -01 and -0s also cause idle_loop to be optimized out.

interesting analysis

It is a good idea to keep idle_loop declared static void. The patch
simply includes a declaration using __attribute__ ((used)) that prevents
the compiler from optimizing out the function.

ah, using "__attribute__ used" was able to find it on google. if anyone cares the url is

http://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html#Function-Attributes

Still I wonder how it will interact with plan9 since I think plan9 uses own compile some part of the code.. not totally sure though.


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