# cat /sys/fs/resctrl/p1/mon_data/mon_L3_00/llc_occupancy
11234000
+
+Intel RDT Errata
+================
+
+Intel MBM Counters May Report System Memory Bandwidth Incorrectly
+-----------------------------------------------------------------
+
+Errata SKX99 for Skylake server and BDF102 for Broadwell server.
+
+Problem: Intel Memory Bandwidth Monitoring (MBM) counters track metrics
+according to the assigned Resource Monitor ID (RMID) for that logical
+core. The IA32_QM_CTR register (MSR 0xC8E), used to report these
+metrics, may report incorrect system bandwidth for certain RMID values.
+
+Implication: Due to the errata, system memory bandwidth may not match
+what is reported.
+
+Workaround: MBM total and local readings are corrected according to the
+following correction factor table:
+
++---------------+---------------+---------------+-----------------+
+|core count |rmid count |rmid threshold |correction factor|
++---------------+---------------+---------------+-----------------+
+|1 |8 |0 |1.000000 |
++---------------+---------------+---------------+-----------------+
+|2 |16 |0 |1.000000 |
++---------------+---------------+---------------+-----------------+
+|3 |24 |15 |0.969650 |
++---------------+---------------+---------------+-----------------+
+|4 |32 |0 |1.000000 |
++---------------+---------------+---------------+-----------------+
+|6 |48 |31 |0.969650 |
++---------------+---------------+---------------+-----------------+
+|7 |56 |47 |1.142857 |
++---------------+---------------+---------------+-----------------+
+|8 |64 |0 |1.000000 |
++---------------+---------------+---------------+-----------------+
+|9 |72 |63 |1.185115 |
++---------------+---------------+---------------+-----------------+
+|10 |80 |63 |1.066553 |
++---------------+---------------+---------------+-----------------+
+|11 |88 |79 |1.454545 |
++---------------+---------------+---------------+-----------------+
+|12 |96 |0 |1.000000 |
++---------------+---------------+---------------+-----------------+
+|13 |104 |95 |1.230769 |
++---------------+---------------+---------------+-----------------+
+|14 |112 |95 |1.142857 |
++---------------+---------------+---------------+-----------------+
+|15 |120 |95 |1.066667 |
++---------------+---------------+---------------+-----------------+
+|16 |128 |0 |1.000000 |
++---------------+---------------+---------------+-----------------+
+|17 |136 |127 |1.254863 |
++---------------+---------------+---------------+-----------------+
+|18 |144 |127 |1.185255 |
++---------------+---------------+---------------+-----------------+
+|19 |152 |0 |1.000000 |
++---------------+---------------+---------------+-----------------+
+|20 |160 |127 |1.066667 |
++---------------+---------------+---------------+-----------------+
+|21 |168 |0 |1.000000 |
++---------------+---------------+---------------+-----------------+
+|22 |176 |159 |1.454334 |
++---------------+---------------+---------------+-----------------+
+|23 |184 |0 |1.000000 |
++---------------+---------------+---------------+-----------------+
+|24 |192 |127 |0.969744 |
++---------------+---------------+---------------+-----------------+
+|25 |200 |191 |1.280246 |
++---------------+---------------+---------------+-----------------+
+|26 |208 |191 |1.230921 |
++---------------+---------------+---------------+-----------------+
+|27 |216 |0 |1.000000 |
++---------------+---------------+---------------+-----------------+
+|28 |224 |191 |1.143118 |
++---------------+---------------+---------------+-----------------+
+
+If rmid > rmid threshold, MBM total and local values should be multiplied
+by the correction factor.
+
+See:
+
+1. Erratum SKX99 in Intel Xeon Processor Scalable Family Specification Update:
+http://web.archive.org/web/20200716124958/https://www.intel.com/content/www/us/en/processors/xeon/scalable/xeon-scalable-spec-update.html
+
+2. Erratum BDF102 in Intel Xeon E5-2600 v4 Processor Product Family Specification Update:
+http://web.archive.org/web/20191125200531/https://www.intel.com/content/dam/www/public/us/en/documents/specification-updates/xeon-e5-v4-spec-update.pdf
+
+3. The errata in Intel Resource Director Technology (Intel RDT) on 2nd Generation Intel Xeon Scalable Processors Reference Manual:
+https://software.intel.com/content/www/us/en/develop/articles/intel-resource-director-technology-rdt-reference-manual.html
+
+for further information.