Re: PREEMPT_RT vs I-PIPE: the numbers, part 2

From: Karim Yaghmour
Date: Wed Jun 22 2005 - 15:02:55 EST

Bill Huey (hui) wrote:
> FreeBSD went through some slow down when they moved to SMPng, but not
> the kind of numbers you show for things surrounding the network stack.
> Something clearly bad happened.

Note that the numbers are not freak accidents, they are consistent
accross the various setups. So in total, that's 15 LMbench runs,
all showing consistent _severe_ cost for preempt_rt. And this despite
the fact that it comes down neck-to-neck with the ipipe on
interrupt response time in those same tests. I would highly suggest
setting up an automated benchmark for automatically running LMbench
on every preempt_rt release and compare that to the vanilla kernel.

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