Messages in this thread Patch in this message | | | From | Anshuman Khandual <> | Subject | [PATCH V5 1/8] perf: Add system error and not in transaction branch types | Date | Mon, 4 Apr 2022 10:20:39 +0530 |
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This expands generic branch type classification by adding two more entries there in i.e system error and not in transaction. This also updates the x86 implementation to process X86_BR_NO_TX records as appropriate. This changes branch types reported to user space on x86 platform but it should not be a problem. The possible scenarios and impacts are enumerated here.
-------------------------------------------------------------------------- | kernel | perf tool | Impact | -------------------------------------------------------------------------- | old | old | Works as before | -------------------------------------------------------------------------- | old | new | PERF_BR_UNKNOWN is processed | -------------------------------------------------------------------------- | new | old | PERF_BR_NO_TX are blocked via old PERF_BR_MAX | -------------------------------------------------------------------------- | new | new | NO_TX are recognized | --------------------------------------------------------------------------
When PERF_BR_NO_TX is blocked via old PERF_BR_MAX (new kernel with old perf tool) the user space might throw up an warning complaining about an unrecognized branch types being reported, but it's expected. PERF_BR_SERROR & PERF_BR_NO_TX branch types will be used for BRBE implementation on arm64 platform.
PERF_BR_NO_TX complements 'abort' and 'in_tx' elements in perf_branch_entry which represent other transaction states for a given branch record. Because this completes the transaction state classification.
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> --- arch/x86/events/intel/lbr.c | 2 +- include/uapi/linux/perf_event.h | 2 ++ 2 files changed, 3 insertions(+), 1 deletion(-)
diff --git a/arch/x86/events/intel/lbr.c b/arch/x86/events/intel/lbr.c index fe1742c4ca49..30dcd18936d5 100644 --- a/arch/x86/events/intel/lbr.c +++ b/arch/x86/events/intel/lbr.c @@ -1336,7 +1336,7 @@ static int branch_map[X86_BR_TYPE_MAP_MAX] = { PERF_BR_IND_CALL, /* X86_BR_IND_CALL */ PERF_BR_UNKNOWN, /* X86_BR_ABORT */ PERF_BR_UNKNOWN, /* X86_BR_IN_TX */ - PERF_BR_UNKNOWN, /* X86_BR_NO_TX */ + PERF_BR_NO_TX, /* X86_BR_NO_TX */ PERF_BR_CALL, /* X86_BR_ZERO_CALL */ PERF_BR_UNKNOWN, /* X86_BR_CALL_STACK */ PERF_BR_IND, /* X86_BR_IND_JMP */ diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h index d37629dbad72..26d8f0b5ac0d 100644 --- a/include/uapi/linux/perf_event.h +++ b/include/uapi/linux/perf_event.h @@ -253,6 +253,8 @@ enum { PERF_BR_COND_RET = 10, /* conditional function return */ PERF_BR_ERET = 11, /* exception return */ PERF_BR_IRQ = 12, /* irq */ + PERF_BR_SERROR = 13, /* system error */ + PERF_BR_NO_TX = 14, /* not in transaction */ PERF_BR_MAX, }; -- 2.25.1
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