Messages in this thread Patch in this message | | | From | Anshuman Khandual <> | Subject | [PATCH V3 03/10] perf: Extend branch type classification | Date | Mon, 14 Mar 2022 11:28:50 +0530 |
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branch_entry.type now has ran out of space to accommodate more branch types classification. This will prevent perf branch stack implementation on arm64 (via BRBE) to capture all available branch types. Extending this bit field i.e branch_entry.type [4 bits] is not an option as it will break user space ABI both for little and big endian perf tools.
Extend branch classification with a new field branch_entry.new_type via a new branch type PERF_BR_EXTEND_ABI in branch_entry.type. Perf tools which could decode PERF_BR_EXTEND_ABI, will then parse branch_entry.new_type as well.
branch_entry.new_type is a 4 bit field which can hold upto 16 branch types. The first three branch types will hold various generic page faults followed by five architecture specific branch types, which can be overridden by the platform for specific use cases. These architecture specific branch types gets overridden on arm64 platform for BRBE implementation.
New generic branch types
- PERF_BR_NEW_FAULT_ALGN - PERF_BR_NEW_FAULT_DATA - PERF_BR_NEW_FAULT_INST
New arch specific branch types
- PERF_BR_NEW_ARCH_1 - PERF_BR_NEW_ARCH_2 - PERF_BR_NEW_ARCH_3 - PERF_BR_NEW_ARCH_4 - PERF_BR_NEW_ARCH_5
Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will@kernel.org> Cc: linux-arm-kernel@lists.infradead.org Cc: linux-perf-users@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> --- include/uapi/linux/perf_event.h | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-)
diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h index 26d8f0b5ac0d..d29280adc3c4 100644 --- a/include/uapi/linux/perf_event.h +++ b/include/uapi/linux/perf_event.h @@ -255,9 +255,22 @@ enum { PERF_BR_IRQ = 12, /* irq */ PERF_BR_SERROR = 13, /* system error */ PERF_BR_NO_TX = 14, /* not in transaction */ + PERF_BR_EXTEND_ABI = 15, /* extend ABI */ PERF_BR_MAX, }; +enum { + PERF_BR_NEW_FAULT_ALGN = 0, /* Alignment fault */ + PERF_BR_NEW_FAULT_DATA = 1, /* Data fault */ + PERF_BR_NEW_FAULT_INST = 2, /* Inst fault */ + PERF_BR_NEW_ARCH_1 = 3, /* Architecture specific */ + PERF_BR_NEW_ARCH_2 = 4, /* Architecture specific */ + PERF_BR_NEW_ARCH_3 = 5, /* Architecture specific */ + PERF_BR_NEW_ARCH_4 = 6, /* Architecture specific */ + PERF_BR_NEW_ARCH_5 = 7, /* Architecture specific */ + PERF_BR_NEW_MAX, +}; + #define PERF_SAMPLE_BRANCH_PLM_ALL \ (PERF_SAMPLE_BRANCH_USER|\ PERF_SAMPLE_BRANCH_KERNEL|\ @@ -1372,7 +1385,8 @@ struct perf_branch_entry { abort:1, /* transaction abort */ cycles:16, /* cycle count to last branch */ type:4, /* branch type */ - reserved:40; + new_type:4, /* additional branch type */ + reserved:36; }; union perf_sample_weight { -- 2.25.1
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