Added a note on performance anomalies for Niagara submitted by Fabian Gorsler.
Added a note on performance anomalies for Niagara submitted by Fabian Gorsler.

arm-hpc/papi,arm-hpc/papi,pyrovski/papi,pyrovski/papi,arm-hpc/papi,arm-hpc/papi,pyrovski/papi,pyrovski/papi,arm-hpc/papi,arm-hpc/papi,pyrovski/papi,arm-hpc/papi,pyrovski/papi,pyrovski/papi,pyrovski/papi