[PATCH] perf script: Update brstack syntax documentation

From: Yujie Liu
Date: Tue Feb 25 2025 - 01:18:24 EST


The following commits appended new fields to the end of the branch info
list, such as branch type and branch speculation info.

commit 1f48989cdc7d ("perf script: Output branch sample type")
commit 6ade6c646035 ("perf script: Show branch speculation info")

Update brstack syntax documentation to be consistent with the latest
branch info list. Improve the descriptions to help users interpret the
fields accurately.

Signed-off-by: Yujie Liu <yujie.liu@xxxxxxxxx>
---
tools/perf/Documentation/perf-script.txt | 16 +++++++++-------
1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/tools/perf/Documentation/perf-script.txt b/tools/perf/Documentation/perf-script.txt
index b72866ef270b..8bd105084280 100644
--- a/tools/perf/Documentation/perf-script.txt
+++ b/tools/perf/Documentation/perf-script.txt
@@ -239,13 +239,15 @@ OPTIONS
i.e., -F "" is not allowed.

The brstack output includes branch related information with raw addresses using the
- /v/v/v/v/cycles syntax in the following order:
- FROM: branch source instruction
- TO : branch target instruction
- M/P/-: M=branch target mispredicted or branch direction was mispredicted, P=target predicted or direction predicted, -=not supported
- X/- : X=branch inside a transactional region, -=not in transaction region or not supported
- A/- : A=TSX abort entry, -=not aborted region or not supported
- cycles
+ FROM/TO/PRED/INTX/ABORT/CYCLES/TYPE/SPEC syntax in the following order:
+ FROM : branch source instruction
+ TO : branch target instruction
+ PRED : M=branch target mispredicted or branch direction was mispredicted, P=target predicted or direction predicted, -=not supported
+ INTX : X=branch inside a transactional region, -=not in transaction region or not supported
+ ABORT : A=TSX abort entry, -=not aborted region or not supported
+ CYCLES: the number of cycles that have elapsed since the last branch was recorded
+ TYPE : branch type
+ SPEC : branch speculation info

The brstacksym is identical to brstack, except that the FROM and TO addresses are printed in a symbolic form if possible.

--
2.34.1