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SubjectRe: [PATCH] Replace completions with semaphores

* Matthew Wilcox <matthew@wil.cx> wrote:

> On Sun, Apr 13, 2008 at 09:05:13AM +0200, Ingo Molnar wrote:
> > there's also another aspect: completions are faster a bit
> > in theory, because they know that they will schedule most of the time -
> > while semaphores assume that they will _not_ schedule. (And that's
> > exactly because the intent of the developer when using a completion is
> > crystal clear.)
>
> In practice though, the current implementation is slower. [...]

any URL to benchmarks?

> [...] Of course, that's fixable, and I strongly suspect that the
> current users of completions simply don't care about speed -- the
> normal use of completions is in startup and shutdown paths where a
> millisecond extra isn't going to be noticable.

completions and semaphores act in the sub-microsecond range, not in the
milliseconds range.

Ingo


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