perf annotate: Save branch counters for each block
When annotating a basic block, it's useful to display the occurrences
of other events in the block.
The branch counter feature is only available for newer Intel platforms.
So a dedicated option to display the branch counters is not introduced.
Reuse the existing --total-cycles option, which triggers the annotation
of a basic block and displays the cycle-related annotation.
When the branch counters information is available, the branch counters
are automatically appended after all the cycle-related annotation.
Accounting the branch counters as well when accounting the cycles in
hist__account_cycles().
In 'struct annotated_branch', introduce a br_cntr array to save the
accumulation of each branch counter.
In a sample, all the branch counters for a branch are saved in a u64
space.
Because the saturation of a branch counter is small, e.g., for Intel
Sierra Forest, the saturation is only 3.
Add ANNOTATION__BR_CNTR_SATURATED_FLAG to indicate if a branch counter
once saturated. That can be used to indicate a potential event lost
because of the saturation.
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: https://lore.kernel.org/r/20240813160208.2493643-5-kan.liang@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>