Messages in this thread |  | | Date | Thu, 1 Feb 2007 19:02:47 +0100 | From | Ingo Molnar <> | Subject | Re: [PATCH 2 of 4] Introduce i386 fibril scheduling |
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* Mark Lord <lkml@rtr.ca> wrote:
> >also, we context-switch kernel threads in 350 nsecs on current > >hardware and the -rt kernel is certainly happy with that and runs all > >hardirqs > > Ingo, how relevant is that "350 nsecs on current hardware" claim? > > I don't mean that in a bad way, but my own experience suggests that > most people doing real hard RT (or tight soft RT) are not doing it on > x86 architectures. But rather on lowly 1GHz (or less) ARM based > processors and the like.
it's not relevant to those embedded boards, but it's relevant to the AIO discussion, which centers around performance.
> For RT issues, those are the platforms I care more about, as those are > the ones that get embedded into real-time devices.
yeah. Nevertheless if you want to use -rt on your desktop (under Fedora 4/5/6) you can track an rpmized+distroized full kernel package quite easily, via 3 easy commands:
cd /etc/yum.repos.d wget http://people.redhat.com/~mingo/realtime-preempt/rt.repo
yum install kernel-rt.x86_64 # on x86_64 yum install kernel-rt # on i686
which is closely tracking latest upstream -git. (for example, the current kernel-rt-2.6.20-rc7.1.rt3.0109.i686.rpm is based on 2.6.20-rc7-git1, so if you want to run a kernel rpm that has all of Linus' latest commits from yesterday, this might be for you.)
it's rumored to be a quite smooth kernel ;-) So in this sense, because this also runs on all my testboxes by default, it matters on modern hardware too, at least to me. Today's commodity hardware is tomorrow's embedded hardware. If a kernel is good on today's colorful desktop hardware then it will be perfect for tomorrow's embedded hardware.
Ingo - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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