mirror of
https://github.com/torvalds/linux.git
synced 2024-12-27 13:22:23 +00:00
29 lines
1.2 KiB
Plaintext
29 lines
1.2 KiB
Plaintext
|
ARM DynamIQ Shared Unit (DSU) PMU
|
||
|
|
==================================
|
||
|
|
|
||
|
|
ARM DynamIQ Shared Unit integrates one or more cores with an L3 memory system,
|
||
|
|
control logic and external interfaces to form a multicore cluster. The PMU
|
||
|
|
allows counting the various events related to the L3 cache, Snoop Control Unit
|
||
|
|
etc, using 32bit independent counters. It also provides a 64bit cycle counter.
|
||
|
|
|
||
|
|
The PMU can only be accessed via CPU system registers and are common to the
|
||
|
|
cores connected to the same DSU. Like most of the other uncore PMUs, DSU
|
||
|
|
PMU doesn't support process specific events and cannot be used in sampling mode.
|
||
|
|
|
||
|
|
The DSU provides a bitmap for a subset of implemented events via hardware
|
||
|
|
registers. There is no way for the driver to determine if the other events
|
||
|
|
are available or not. Hence the driver exposes only those events advertised
|
||
|
|
by the DSU, in "events" directory under :
|
||
|
|
|
||
|
|
/sys/bus/event_sources/devices/arm_dsu_<N>/
|
||
|
|
|
||
|
|
The user should refer to the TRM of the product to figure out the supported events
|
||
|
|
and use the raw event code for the unlisted events.
|
||
|
|
|
||
|
|
The driver also exposes the CPUs connected to the DSU instance in "associated_cpus".
|
||
|
|
|
||
|
|
|
||
|
|
e.g usage :
|
||
|
|
|
||
|
|
perf stat -a -e arm_dsu_0/cycles/
|