Re: [announce] [patch] Voluntary Kernel Preemption Patch

Robert Love
2004-07-11T23:11:28Z

On Sun, 2004-07-11 at 12:30 +0200, Ingo Molnar wrote:

> the reason is difference in overhead (codesize, speed) and risks (driver
> robustness). We do not want to enable preempt for Fedora yet because it
> breaks just too much stuff and is too heavy. So we looked for a solution
> that might work for a generic distro.

I think we should work toward being able to enable kernel preemption in
Fedora, then, instead of other tangential solutions.

And I disagree with the overhead argument. I have seen no specific
arguments that show a significant overhead. Heck, when people tried to
show that kernel preemption hurt throughput, we saw tests that showed
improved throughput (probably due to better utilization of I/O).

But stability is a subjective argument (and I agree we need more driver
love, at least for obscure drivers) wrt kernel preemption. So I would
say we should concentrate on working on the stability[1] so we could
just enable kernel preemption unconditionally and not designing new
solutions.

Best,

Robert Love

[1] What better way than enabling CONFIG_PREEMPT for Fedora? Enable it
for Fedora, and do not enable it for Red Hat Enterprise until you are
confidant. ;-)