Re: [PATCH 1/7] posix-timers: tidy up clock interfaces and consolidatedispatch logic
From: George Anzinger
Date: Mon Jan 24 2005 - 21:16:56 EST
Where were you when I was writing this stuff :). I agree with most all of it,
save the following:
> /*
> + * Define this to initialize every k_clock function table so all its
> + * function pointers are non-null, and always do indirect calls through the
> + * table. Leave it undefined to instead leave null function pointers and
> + * decide at the call sites between a direct call (maybe inlined) to the
> + * default function and an indirect call through the table when it's filled
> + * in. Which style is preferable is whichever performs better in the
> + * common case of using the default functions.
> +#define CLOCK_DISPATCH_DIRECT
As I understand it modern machines, the indirect call does really bad things to
the pipeline. The default call, even preceeded by the if, will be much faster
by this reasoning. I would, therefor, prefer not defining CLOCK_DISPATCH_DIRECT.
--
George Anzinger george@xxxxxxxxxx
High-res-timers: http://sourceforge.net/projects/high-res-timers/
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