Messages in this thread | | | Date | Fri, 15 Oct 2004 01:46:03 +0200 | From | Ingo Molnar <> | Subject | Re: [patch] Real-Time Preemption, -VP-2.6.9-rc4-mm1-U0 |
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* Karim Yaghmour <karim@opersys.com> wrote:
> > Ingo Molnar wrote: > > http://redhat.com/~mingo/voluntary-preempt/voluntary-preempt-2.6.9-rc4-mm1-U0 > > I notice: > + local_irq_save(flags); > + ____trace(&__get_cpu_var(trace), eip, parent_eip); > + local_irq_restore(flags); > > Why not use the lockless logging available in relayfs, you'll avoid > the interrupt disabling altogether since, umm ... it's lockless.
i just added something ad-hoc. I wanted it to be accurate across interrupt entries. I have not looked at the relayfs locking but how does it solve that? Also, cli/sti makes it obviously SMP-safe and is pretty cheap on all x86 CPUs. (Also, i didnt want to use preempt_disable/enable because the tracer interacts with that code quite heavily.)
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