On Sat, 22 Mar 1997, Darren Senn wrote:
> Ted said:
> > This is still false optimization. If someone is polling for data, the
> > amount of time taken to do the context switch is *so* *large* that the
> > time to do the extra two comparisons is lost in the noise.
>
> Oh, granted, on both counts. I was merely arguing against the assumption
> that select() wouldn't be used in that context.
>
> > It has nothing to do with select()'s interface as much as it has to do
> > with generic system call overhead. As far as your claim that there's a
> > quite a body of code that does it, what programs do this? They really
> > are quite broken.....
>
> Real time applications mostly. Two reasons: it is more important that a
> real time app take the same amount of time in every pass through its innermost
> code than it is for the average time to be small, and many real time os's
> have much less system call overhead than Linux does (read: no context switch).
> Now I know that the whole real time os thing is an old argument that's been
> beat to death in the Linux community, and is a sore point with a lot of
> people ("Linux isn't real time!") but my point stands: select() gets used
> in inner loops.
>