* 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 > events? 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. Thanks, Ingo -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
