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- Qualcomm Technologies Level-2 Cache Performance Monitoring Unit (PMU)
- =====================================================================
- This driver supports the L2 cache clusters found in Qualcomm Technologies
- Centriq SoCs. There are multiple physical L2 cache clusters, each with their
- own PMU. Each cluster has one or more CPUs associated with it.
- There is one logical L2 PMU exposed, which aggregates the results from
- the physical PMUs.
- The driver provides a description of its available events and configuration
- options in sysfs, see /sys/devices/l2cache_0.
- The "format" directory describes the format of the events.
- Events can be envisioned as a 2-dimensional array. Each column represents
- a group of events. There are 8 groups. Only one entry from each
- group can be in use at a time. If multiple events from the same group
- are specified, the conflicting events cannot be counted at the same time.
- Events are specified as 0xCCG, where CC is 2 hex digits specifying
- the code (array row) and G specifies the group (column) 0-7.
- In addition there is a cycle counter event specified by the value 0xFE
- which is outside the above scheme.
- The driver provides a "cpumask" sysfs attribute which contains a mask
- consisting of one CPU per cluster which will be used to handle all the PMU
- events on that cluster.
- Examples for use with perf:
- perf stat -e l2cache_0/config=0x001/,l2cache_0/config=0x042/ -a sleep 1
- perf stat -e l2cache_0/config=0xfe/ -C 2 sleep 1
- The driver does not support sampling, therefore "perf record" will
- not work. Per-task perf sessions are not supported.
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