Messages in this thread | | | Date | Thu, 22 Oct 2015 11:06:32 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH V5 1/1] bpf: control events stored in PERF_EVENT_ARRAY maps trace data output when perf sampling |
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On Wed, Oct 21, 2015 at 02:19:49PM -0700, Alexei Starovoitov wrote:
> >Urgh, that's still horridly inconsistent. Can we please come up with a > >consistent interface to perf?
> My suggestion was to do ioctl(enable/disable) of events from userspace > after receiving notification from kernel via my bpf_perf_event_output() > helper.
> Wangnan's argument was that display refresh happens often and it's fast, > so the time taken by user space to enable events on all cpus is too > slow and ioctl does ipi and disturbs other cpus even more. > So soft_disable done by the program to enable/disable particular events > on all cpus kinda makes sense.
And this all makes me think I still have no clue what you're all trying to do here.
Who cares about display updates and why. And why should there be an active userspace part to eBPF programs?
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