Messages in this thread | | | Date | Tue, 19 Apr 2022 14:55:42 +0100 | Subject | Re: [PATCH V5 1/8] perf: Add system error and not in transaction branch types | From | James Clark <> |
| |
On 04/04/2022 05:50, Anshuman Khandual wrote: > 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>
Reviewed-by: James Clark <james.clark@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, > }; >
| |