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1=====================================================================2Qualcomm Technologies Level-2 Cache Performance Monitoring Unit (PMU)3=====================================================================4 5This driver supports the L2 cache clusters found in Qualcomm Technologies6Centriq SoCs. There are multiple physical L2 cache clusters, each with their7own PMU. Each cluster has one or more CPUs associated with it.8 9There is one logical L2 PMU exposed, which aggregates the results from10the physical PMUs.11 12The driver provides a description of its available events and configuration13options in sysfs, see /sys/bus/event_source/devices/l2cache_0.14 15The "format" directory describes the format of the events.16 17Events can be envisioned as a 2-dimensional array. Each column represents18a group of events. There are 8 groups. Only one entry from each19group can be in use at a time. If multiple events from the same group20are specified, the conflicting events cannot be counted at the same time.21 22Events are specified as 0xCCG, where CC is 2 hex digits specifying23the code (array row) and G specifies the group (column) 0-7.24 25In addition there is a cycle counter event specified by the value 0xFE26which is outside the above scheme.27 28The driver provides a "cpumask" sysfs attribute which contains a mask29consisting of one CPU per cluster which will be used to handle all the PMU30events on that cluster.31 32Examples for use with perf::33 34 perf stat -e l2cache_0/config=0x001/,l2cache_0/config=0x042/ -a sleep 135 36 perf stat -e l2cache_0/config=0xfe/ -C 2 sleep 137 38The driver does not support sampling, therefore "perf record" will39not work. Per-task perf sessions are not supported.40