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authorLinus Torvalds <torvalds@linux-foundation.org>2025-06-06 11:50:47 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2025-06-06 11:50:47 -0700
commitc26f4fbd58375bd6ef74f95eb73d61762ad97c59 (patch)
tree0bec60c3a022bfe531420265f1b489ee4aaa1eb1 /Documentation/trace
parenta100922a3855eb35ecd465f1d558546b1e144445 (diff)
parent9857af0fcff385c75433f2162c30c62eb912ef6d (diff)
Merge tag 'char-misc-6.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc
Pull char / misc / iio driver updates from Greg KH: "Here is the big char/misc/iio and other small driver subsystem pull request for 6.16-rc1. Overall, a lot of individual changes, but nothing major, just the normal constant forward progress of new device support and cleanups to existing subsystems. Highlights in here are: - Large IIO driver updates and additions and device tree changes - Android binder bugfixes and logfile fixes - mhi driver updates - comedi driver updates - counter driver updates and additions - coresight driver updates and additions - echo driver removal as there are no in-kernel users of it - nvmem driver updates - spmi driver updates - new amd-sbi driver "subsystem" and drivers added - rust miscdriver binding documentation fix - other small driver fixes and updates (uio, w1, acrn, hpet, xillybus, cardreader drivers, fastrpc and others) All of these have been in linux-next for quite a while with no reported problems" * tag 'char-misc-6.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (390 commits) binder: fix yet another UAF in binder_devices counter: microchip-tcb-capture: Add watch validation support dt-bindings: iio: adc: Add ROHM BD79100G iio: adc: add support for Nuvoton NCT7201 dt-bindings: iio: adc: add NCT7201 ADCs iio: chemical: Add driver for SEN0322 dt-bindings: trivial-devices: Document SEN0322 iio: adc: ad7768-1: reorganize driver headers iio: bmp280: zero-init buffer iio: ssp_sensors: optimalize -> optimize HID: sensor-hub: Fix typo and improve documentation iio: admv1013: replace redundant ternary operator with just len iio: chemical: mhz19b: Fix error code in probe() iio: adc: at91-sama5d2: use IIO_DECLARE_BUFFER_WITH_TS iio: accel: sca3300: use IIO_DECLARE_BUFFER_WITH_TS iio: adc: ad7380: use IIO_DECLARE_DMA_BUFFER_WITH_TS iio: adc: ad4695: rename AD4695_MAX_VIN_CHANNELS iio: adc: ad4695: use IIO_DECLARE_DMA_BUFFER_WITH_TS iio: introduce IIO_DECLARE_BUFFER_WITH_TS macros iio: make IIO_DMA_MINALIGN minimum of 8 bytes ...
Diffstat (limited to 'Documentation/trace')
-rw-r--r--Documentation/trace/coresight/coresight-perf.rst31
1 files changed, 31 insertions, 0 deletions
diff --git a/Documentation/trace/coresight/coresight-perf.rst b/Documentation/trace/coresight/coresight-perf.rst
index d087aae7d492..30be89320621 100644
--- a/Documentation/trace/coresight/coresight-perf.rst
+++ b/Documentation/trace/coresight/coresight-perf.rst
@@ -78,6 +78,37 @@ enabled like::
Please refer to the kernel configuration help for more information.
+Fine-grained tracing with AUX pause and resume
+----------------------------------------------
+
+Arm CoreSight may generate a large amount of hardware trace data, which
+will lead to overhead in recording and distract users when reviewing
+profiling result. To mitigate the issue of excessive trace data, Perf
+provides AUX pause and resume functionality for fine-grained tracing.
+
+The AUX pause and resume can be triggered by associated events. These
+events can be ftrace tracepoints (including static and dynamic
+tracepoints) or PMU events (e.g. CPU PMU cycle event). To create a perf
+session with AUX pause / resume, three configuration terms are
+introduced:
+
+- "aux-action=start-paused": it is specified for the cs_etm PMU event to
+ launch in a paused state.
+- "aux-action=pause": an associated event is specified with this term
+ to pause AUX trace.
+- "aux-action=resume": an associated event is specified with this term
+ to resume AUX trace.
+
+Example for triggering AUX pause and resume with ftrace tracepoints::
+
+ perf record -e cs_etm/aux-action=start-paused/k,syscalls:sys_enter_openat/aux-action=resume/,syscalls:sys_exit_openat/aux-action=pause/ ls
+
+Example for triggering AUX pause and resume with PMU event::
+
+ perf record -a -e cs_etm/aux-action=start-paused/k \
+ -e cycles/aux-action=pause,period=10000000/ \
+ -e cycles/aux-action=resume,period=1050000/ -- sleep 1
+
Perf test - Verify kernel and userspace perf CoreSight work
-----------------------------------------------------------