Re: RT patch acceptance

Daniel Walker
2005-05-24T18:03:48Z

On Tue, 2005-05-24 at 10:15 +0200, Ingo Molnar wrote:
> * Nick Piggin <nickpiggin@yahoo.com.au> wrote:
>
> > Of course this is weighed off against the improvements added to the
> > kernel. I'm personally not too clear on what those improvements are; a
> > bit better soft-realtime response? (I don't know) [...]
>
> what the -RT kernel (PREEMPT_RT) offers are guaranteed hard-realtime
> responses. ~15 usecs worst-case latency on a 2GHz Athlon64. On arbitrary
> (SCHED_OTHER) workloads. (I.e. i've measured such worst-case latencies
> when running 1000 hackbench tasks or when swapping the box to death, or
> when running 40 parallel copies of the LTP testsuite.)

I wouldn't start making guarantees yet .. For instance printk can hold
off interrupts for unknown periods (unknown to me anyway) depending on
the size of the strings that it prints.

Daniel