perf_linux plugin doesn't report metrics when it is configured with multiple CPUs

[bobpiece]

Host operating system: output of uname -a

Linux r2-compute-29 4.15.0-91-generic #92-Ubuntu SMP Fri Feb 28 11:09:48 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux

node_exporter version: output of node_exporter --version

node_exporter, version 1.0.0-rc.0 (branch: master, revision: 99182a3)
build user: ubuntu@r2-compute-29
build date: 20200323-20:05:30
go version: go1.14.1

node_exporter command line flags

node_exporter --collector.disable-defaults --collector.perf --collector.perf.cpus=0-13 --log.level=debug

Are you running node_exporter in Docker?

no

What did you do that produced an error?

Run NodeExporter with perf plugin enabled (plugin has to be configured for more than one CPU)

What did you expect to see?

Metrics for each configured CPU

What did you see instead?

Node exporter exposes metrics only for CPU-0, information about other CPUs is not visible.