Add dependencies needed to build rtla with BPF sample collection support to README, and document both ways of sample collection in the manpages. Signed-off-by: Tomas Glozar <tglozar@xxxxxxxxxx> --- Documentation/tools/rtla/common_timerlat_description.rst | 8 ++++++++ tools/tracing/rtla/README.txt | 7 +++++++ 2 files changed, 15 insertions(+) diff --git a/Documentation/tools/rtla/common_timerlat_description.rst b/Documentation/tools/rtla/common_timerlat_description.rst index 8cd3e717baa8..49fcae3ffdec 100644 --- a/Documentation/tools/rtla/common_timerlat_description.rst +++ b/Documentation/tools/rtla/common_timerlat_description.rst @@ -8,3 +8,11 @@ The *timerlat* tracer outputs information in two ways. It periodically prints the timer latency at the timer *IRQ* handler and the *Thread* handler. It also enables the trace of the most relevant information via **osnoise:** tracepoints. + +The **rtla timerlat** tool sets the options of the *timerlat* tracer +and collects and displays a summary of the results. By default, +the collection is done synchronously in kernel space using a dedicated +BPF program attached to the *timerlat* tracer. If either BPF or +the **osnoise:timerlat_sample** tracepoint it attaches to is +unavailable, the **rtla timerlat** tool falls back to using tracefs to +process the data asynchronously in user space. diff --git a/tools/tracing/rtla/README.txt b/tools/tracing/rtla/README.txt index dd5621038c55..43e98311d10f 100644 --- a/tools/tracing/rtla/README.txt +++ b/tools/tracing/rtla/README.txt @@ -13,6 +13,13 @@ RTLA depends on the following libraries and tools: - libtraceevent - libcpupower (optional, for --deepest-idle-state) +For BPF sample collection support, the following extra dependencies are +required: + + - libbpf 1.0.0 or later + - bpftool with skeleton support + - clang with BPF CO-RE support + It also depends on python3-docutils to compile man pages. For development, we suggest the following steps for compiling rtla: -- 2.48.1
