On Mon, Feb 26, 2018 at 05:53:57PM -0800, skan...@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". When I > say clusters, I using the more common interpretation of "homogeneous CPUs > running on the same clock"/CPUs in a cpufreq policy and not ARM's new > redefinition of cluster. So, on a SoC with 4 little and 4 big cores, it'll > still trigger a lot of unnecessary smp calls/IPIs that cause unnecessary > wakeups.
arch/arm64/include/asm/topology.h:#define topology_physical_package_id(cpu) (cpu_topology[cpu].cluster_id) *sigh*... that's just broken...
