Re: [RFC/Requirements/Design] h/w error reporting

[Ingo Molnar]

* Peter Zijlstra <a.p.zijlstra@xxxxxxxxx> wrote:

> On Wed, 2010-11-10 at 10:23 -0800, Luck, Tony wrote:
> > > A few of things that pop up quickly are:
> > >
> > > 1) lockless
> > 
> > This is a clear requirement for use in h/w error
> > reporting too.  Taking locks in NMI or machine
> > check handler isn't an option.
> 
> Don't worry, lots of PMIs are NMIs, perf needs to be fully NMI safe
> otherwise things simply don't work.

Yep, in fact perf was fully NMI safe earlier than the ftrace ring-buffer.

When perf code is NMI unsafe we notice it very quickly. I regularly record millions 
of events per second.

Thanks,

	Ingo
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