Based on kernel version 4.16.1. Page generated on 2018-04-09 11:53 EST.
1 Qualcomm Technologies Level-2 Cache Performance Monitoring Unit (PMU) 2 ===================================================================== 3 4 This driver supports the L2 cache clusters found in Qualcomm Technologies 5 Centriq SoCs. There are multiple physical L2 cache clusters, each with their 6 own PMU. Each cluster has one or more CPUs associated with it. 7 8 There is one logical L2 PMU exposed, which aggregates the results from 9 the physical PMUs. 10 11 The driver provides a description of its available events and configuration 12 options in sysfs, see /sys/devices/l2cache_0. 13 14 The "format" directory describes the format of the events. 15 16 Events can be envisioned as a 2-dimensional array. Each column represents 17 a group of events. There are 8 groups. Only one entry from each 18 group can be in use at a time. If multiple events from the same group 19 are specified, the conflicting events cannot be counted at the same time. 20 21 Events are specified as 0xCCG, where CC is 2 hex digits specifying 22 the code (array row) and G specifies the group (column) 0-7. 23 24 In addition there is a cycle counter event specified by the value 0xFE 25 which is outside the above scheme. 26 27 The driver provides a "cpumask" sysfs attribute which contains a mask 28 consisting of one CPU per cluster which will be used to handle all the PMU 29 events on that cluster. 30 31 Examples for use with perf: 32 33 perf stat -e l2cache_0/config=0x001/,l2cache_0/config=0x042/ -a sleep 1 34 35 perf stat -e l2cache_0/config=0xfe/ -C 2 sleep 1 36 37 The driver does not support sampling, therefore "perf record" will 38 not work. Per-task perf sessions are not supported.