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 <[email protected]> --- .../tools/rtla/common_timerlat_options.txt | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/Documentation/tools/rtla/common_timerlat_options.txt b/Documentation/tools/rtla/common_timerlat_options.txt index 0cf7eca1f7b6..07a285fcf7cf 100644 --- a/Documentation/tools/rtla/common_timerlat_options.txt +++ b/Documentation/tools/rtla/common_timerlat_options.txt @@ -65,3 +65,21 @@ 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``, stored in an ELF section with the ``tp_`` prefix. + The prefix is used by libbpf to set BPF program type to BPF_PROG_TYPE_TRACEPOINT. + + 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 falls back to tracefs mode and BPF actions are not supported. -- 2.51.1
