requires a deep understanding of the Coresight HW. The following sections
provide details on using both methods.
-1) Using the sysFS interface:
+Using the sysFS interface
+~~~~~~~~~~~~~~~~~~~~~~~~~
Before trace collection can start, a coresight sink needs to be identified.
There is no limit on the amount of sinks (nor sources) that can be enabled at
Instruction 0 0x8026B588 E8BD8000 true LDM sp!,{pc}
Timestamp Timestamp: 17107041535
-2) Using perf framework:
+Using perf framework
+~~~~~~~~~~~~~~~~~~~~
Coresight tracers are represented using the Perf framework's Performance
Monitoring Unit (PMU) abstraction. As such the perf framework takes charge of
the perf tools can be found in the "HOWTO.md" file of the openCSD gitHub
repository [#third]_.
-2.1) AutoFDO analysis using the perf tools:
+Advanced perf framework usage
+-----------------------------
+
+AutoFDO analysis using the perf tools
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
perf can be used to record and analyze trace of programs.
Note that only 64-bit programs are currently supported - further work is
required to support instruction decode of 32-bit Arm programs.
-2.2) Tracing PID
+Tracing PID
+~~~~~~~~~~~
The kernel can be built to write the PID value into the PE ContextID registers.
For a kernel running at EL1, the PID is stored in CONTEXTIDR_EL1. A PE may
Generating coverage files for Feedback Directed Optimization: AutoFDO
----------------------------------------------------------------------
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
'perf inject' accepts the --itrace option in which case tracing data is
removed and replaced with the synthesized events. e.g.