Re: [PATCH] Return value from schedule()

From: Matthew Wilcox
Date: Thu Sep 04 2008 - 12:21:26 EST


On Thu, Sep 04, 2008 at 06:14:24PM +0200, Ingo Molnar wrote:
> > If schedule() returned whether or not it had scheduled another task, we
> > could do something like:
> >
> > if (!schedule())
> > udelay(10);
>
> hm, i'm not really sure - this really just seems to be a higher prio
> variant of yield() combined with some weird code. Do we really want to
> promote such arguably broken behavior? If there's any chance of any
> polling to take a material amount of CPU time it should be event driven
> to begin with.

Oh, I'm not concerned about CPU utilisation, I'm concerned about PCI bus
utilisation. Perhaps I'd like a yield_timeout() function instead where
I say that I'd like to not run for at least 10 microseconds?

Can we do that, or are we still jiffie-based there?

--
Matthew Wilcox Intel Open Source Technology Centre
"Bill, look, we understand that you're interested in selling us this
operating system, but compare it to ours. We can't possibly take such
a retrograde step."
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/