Messages in this thread | | | Date | Tue, 27 Feb 2018 11:52:25 +0000 | From | Mark Rutland <> | Subject | Re: [PATCH v1 2/2] perf/core: Add support for PMUs that can be read from any CPU |
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On Mon, Feb 26, 2018 at 05:53:57PM -0800, skannan@codeaurora.org wrote: > On 2018-02-24 00:41, Peter Zijlstra wrote: > > On Fri, Feb 23, 2018 at 04:19:38PM -0800, Saravana Kannan wrote: > > > Some PMUs events can be read from any CPU. So allow the PMU to mark > > > events as such. For these events, we don't need to reject reads or > > > make smp calls to the event's CPU and cause unnecessary wake ups. > > > > > > Good examples of such events would be events from caches shared across > > > all CPUs. > > > > So why would the existing ACTIVE_PKG not work for you? Because clearly > > your example does not cross a package. > > Because based on testing it on hardware, it looks like the two clusters in > an ARM DynamIQ design are not considered part of the same "package".
I don't think we should consider the topology masks at all for system PMU affinity. Due to the number of ways these can be integrated, and the lack of a standard(ish) topology across arm platforms.
IIUC, there's ongoing work to try to clean that up, but that won't give us anything meaningful for PMU affinity.
If we need a mask, that should be something the FW description of the PMU provides, and the PMU driver provides to the core code.
Thanks, Mark.
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