Add new option --bpf-action into common_timerlat_options.txt, including
the format in which it takes the BPF program, and a reference to an
example.
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
---
.../tools/rtla/common_timerlat_options.rst | 20 +++++++++++++++++++
1 file changed, 20 insertions(+)
diff --git a/Documentation/tools/rtla/common_timerlat_options.rst b/Documentation/tools/rtla/common_timerlat_options.rst
index c6046fcf52dc..7e08a27e87fe 100644
--- a/Documentation/tools/rtla/common_timerlat_options.rst
+++ b/Documentation/tools/rtla/common_timerlat_options.rst
@@ -65,3 +65,23 @@
Set timerlat to run without workload, waiting for the user to dispatch a per-cpu
task that waits for a new period on the tracing/osnoise/per_cpu/cpu$ID/timerlat_fd.
See linux/tools/rtla/example/timerlat_load.py for an example of user-load code.
+
+**--bpf-action** *bpf-program*
+
+ Loads a BPF program from an ELF file and executes it when a latency threshold is exceeded.
+
+ The BPF program must be a valid ELF file loadable with libbpf. The program must contain
+ a function named ``action_handler``, declared with ``SEC("tp/timerlat_action")`` or
+ a different section name beginning with "tp/". This tells libbpf that the program type is
+ BPF_PROG_TYPE_TRACEPOINT, without it, the program will not be loaded properly.
+
+ The program receives a ``struct trace_event_raw_timerlat_sample`` parameter
+ containing timerlat sample data.
+
+ An example is provided in ``tools/tracing/rtla/example/timerlat_bpf_action.c``.
+ This example demonstrates how to create a BPF program that prints latency information using
+ bpf_trace_printk() when a threshold is exceeded.
+
+ **Note**: BPF actions require BPF support to be available. If BPF is not available
+ or disabled, the tool will fall back to tracefs mode and BPF actions will not be
+ supported.
--
2.51.0