Re: [RFC] ACPI, APEI, Generic Hardware Error Source (GHES) injectingsupport
From: Ingo Molnar
Date: Fri May 20 2011 - 07:53:34 EST
* Borislav Petkov <bp@xxxxxxxxx> wrote:
> On Tue, May 17, 2011 at 09:18:03PM +0200, Ingo Molnar wrote:
> > So for example [sufficienty privileged] user-space could inject *any*
> > perf event - for example a PERF_COUNT_HW_CACHE_MISSES event (for test
> > purposes) and any tooling that runs could not tell apart this injected
> > event from a real event.
> Yeah about that, I was recently speculating how that would work. So do we do
> $ perf record ...
> in the one xterm, and, in the other,
> $ perf inject
> so that while recording, we can inject some events from userspace? Or
> do we inject it, it gets buffered somewhere in the meantime and then
> the next perf record session sees it along with the remaining injection
Well, for persistent events there would be interim buffering even if there's no
observation going on anywhere. I.e. there's always an 'observer' of events.
For non-persistent events, if they are injected, then they are like trace
events for which nobody is interested in: they are lost.
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