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perf script: Update brstack syntax documentation

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The following commits added new fields/flags to the branch stack field
list:

commit 1f48989cdc ("perf script: Output branch sample type")
commit 6ade6c6460 ("perf script: Show branch speculation info")
commit 1e66dcff7b ("perf script: Add not taken event for branch stack")

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

Signed-off-by: Yujie Liu <yujie.liu@intel.com>
Reviewed-by: Leo Yan <leo.yan@arm.com>
Reviewed-by: Sandipan Das <sandipan.das@amd.com>
Link: https://lore.kernel.org/r/20250312072329.419020-1-yujie.liu@intel.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
This commit is contained in:
Yujie Liu
2025-03-14 10:41:08 -07:00
committed by Namhyung Kim
parent 2f39edece1
commit fa9bc517af
1 changed files with 16 additions and 7 deletions
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tools/perf/Documentation/perf-script.txt
+16 -7
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@@ -239,13 +239,22 @@ 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/EVENT/INTX/ABORT/CYCLES/TYPE/SPEC syntax in the following order:
FROM : branch source instruction
TO : branch target instruction
EVENT : M=branch target or direction was mispredicted
P=branch target or direction was predicted
N=branch not-taken
-=no event or not supported
INTX : X=branch inside a transactional region
-=branch 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: COND/UNCOND/IND/CALL/IND_CALL/RET etc.
-=not supported
SPEC : branch speculation info: SPEC_WRONG_PATH/NON_SPEC_CORRECT_PATH/SPEC_CORRECT_PATH
-=not supported
The brstacksym is identical to brstack, except that the FROM and TO addresses are printed in a symbolic form if possible.