qcom_l3_pmu.rst (1419B)
1=========================================================================== 2Qualcomm Datacenter Technologies L3 Cache Performance Monitoring Unit (PMU) 3=========================================================================== 4 5This driver supports the L3 cache PMUs found in Qualcomm Datacenter Technologies 6Centriq SoCs. The L3 cache on these SOCs is composed of multiple slices, shared 7by all cores within a socket. Each slice is exposed as a separate uncore perf 8PMU with device name l3cache_<socket>_<instance>. User space is responsible 9for aggregating across slices. 10 11The driver provides a description of its available events and configuration 12options in sysfs, see /sys/devices/l3cache*. Given that these are uncore PMUs 13the driver also exposes a "cpumask" sysfs attribute which contains a mask 14consisting of one CPU per socket which will be used to handle all the PMU 15events on that socket. 16 17The hardware implements 32bit event counters and has a flat 8bit event space 18exposed via the "event" format attribute. In addition to the 32bit physical 19counters the driver supports virtual 64bit hardware counters by using hardware 20counter chaining. This feature is exposed via the "lc" (long counter) format 21flag. E.g.:: 22 23 perf stat -e l3cache_0_0/read-miss,lc/ 24 25Given that these are uncore PMUs the driver does not support sampling, therefore 26"perf record" will not work. Per-task perf sessions are not supported.