trace/coresight/coresight-config.rst

1 .. SPDX-License-Identifier: GPL-2.0
4 CoreSight System Configuration Manager
13 The CoreSight System Configuration manager is an API that allows the
14 programming of the CoreSight system with pre-defined configurations that
17 Many CoreSight components can be programmed in complex ways - especially ETMs.
18 In addition, components can interact across the CoreSight system, often via
19 the cross trigger components such as CTI and CTM. These system settings can
26 This section introduces the basic concepts of a CoreSight system configuration.
30 --------
32 A feature is a named set of programming for a CoreSight device. The programming
38 CoreSight device is registered with the configuration manager.
41 accesses in the driver - the resource usage and parameter descriptions
66 Users can update parameter values using the configfs API for the CoreSight
67 system - which is described below.
74 --------------
82 enabled on a class of devices - i.e. any ETMv4, or specific devices, e.g. a
83 specific CTI on the system.
113    associated feature 'strobing' that works on ETMv4 CoreSight Devices.
118     perf record -e cs_etm/autofdo/ myapp
139 Mount configfs as normal and the 'cs-syscfg' subsystem will appear::
142     cs-syscfg  stp-policy
144 This has two sub-directories::
146     $ cd cs-syscfg/
174 using CoreSight with sysfs.
212 The configurations loaded into the CoreSight configuration management are
220 The key directory here is 'events' - a generic perf directory which allows
234     $ perf record -e cs_etm/autofdo/u --per-thread <application>
238     $ perf record -e cs_etm/autofdo,preset=1/u --per-thread <application>
246 Coresight can be controlled using sysfs. When this is in use then a configuration
256 This will then use any default parameter values in the features - which can be
264 The valid values for preset are 0 - to deselect presets, and any value of
265 <n> where a preset<n> sub-directory is present.
283 An example of a custom configuration is found in ./samples/coresight.