Messages in this thread Patch in this message | | | Subject | Re: [RFC V1 10/11] perf: Expand perf_branch_entry.type | From | James Clark <> | Date | Tue, 25 Jan 2022 16:58:20 +0000 |
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On 24/01/2022 04:30, Anshuman Khandual wrote: > Current perf_branch_entry.type is a 4 bits field just enough to accommodate > 16 generic branch types. This is insufficient to accommodate platforms like > arm64 which has much more branch types. Lets just expands this field into a > 6 bits one, which can now hold 64 generic branch types. This also adds more > generic branch types and updates the BRBE driver as required. > > 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: 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> > --- > drivers/perf/arm_pmu_brbe.c | 7 ++++++- > include/uapi/linux/perf_event.h | 10 ++++++++-- > tools/include/uapi/linux/perf_event.h | 10 ++++++++-- > tools/perf/util/branch.c | 8 +++++++- > 4 files changed, 29 insertions(+), 6 deletions(-) > > diff --git a/drivers/perf/arm_pmu_brbe.c b/drivers/perf/arm_pmu_brbe.c > index 8d27ad868359..7cd1208c6c58 100644 > --- a/drivers/perf/arm_pmu_brbe.c > +++ b/drivers/perf/arm_pmu_brbe.c > @@ -253,12 +253,17 @@ static int brbe_fetch_perf_type(u64 brbinf) > case BRBINF_TYPE_DEBUG_EXIT: > return PERF_BR_DEBUG_EXIT; > case BRBINF_TYPE_SERROR: > + return PERF_BR_SERROR; > case BRBINF_TYPE_INST_DEBUG: > + return PERF_BR_DEBUG_INST; > case BRBINF_TYPE_DATA_DEBUG: > + return PERF_BR_DEBUG_DATA; > case BRBINF_TYPE_ALGN_FAULT: > + return PERF_BR_FAULT_ALGN; > case BRBINF_TYPE_INST_FAULT: > + return PERF_BR_FAULT_INST; > case BRBINF_TYPE_DATA_FAULT: > - return PERF_BR_UNKNOWN; > + return PERF_BR_FAULT_DATA; > default: > pr_warn("unknown branch type captured\n"); > return PERF_BR_UNKNOWN; > diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h > index b91d0f575d0c..361fdc6b87a0 100644 > --- a/include/uapi/linux/perf_event.h > +++ b/include/uapi/linux/perf_event.h > @@ -256,6 +256,12 @@ enum { > PERF_BR_FIQ = 13, /* fiq */ > PERF_BR_DEBUG_HALT = 14, /* debug halt */ > PERF_BR_DEBUG_EXIT = 15, /* debug exit */ > + PERF_BR_DEBUG_INST = 16, /* instruciton debug */ > + PERF_BR_DEBUG_DATA = 17, /* data debug */ > + PERF_BR_FAULT_ALGN = 18, /* alignment fault */ > + PERF_BR_FAULT_DATA = 19, /* data fault */ > + PERF_BR_FAULT_INST = 20, /* instruction fault */ > + PERF_BR_SERROR = 21, /* system error */ > PERF_BR_MAX, > }; > > @@ -1370,8 +1376,8 @@ struct perf_branch_entry { > in_tx:1, /* in transaction */ > abort:1, /* transaction abort */ > cycles:16, /* cycle count to last branch */ > - type:4, /* branch type */ > - reserved:40; > + type:6, /* branch type */ > + reserved:38; > }; > > union perf_sample_weight { > diff --git a/tools/include/uapi/linux/perf_event.h b/tools/include/uapi/linux/perf_event.h > index 1882054e8684..9a82b8aaed93 100644 > --- a/tools/include/uapi/linux/perf_event.h > +++ b/tools/include/uapi/linux/perf_event.h > @@ -256,6 +256,12 @@ enum { > PERF_BR_FIQ = 13, /* fiq */ > PERF_BR_DEBUG_HALT = 14, /* debug halt */ > PERF_BR_DEBUG_EXIT = 15, /* debug exit */ > + PERF_BR_DEBUG_INST = 16, /* instruciton debug */ > + PERF_BR_DEBUG_DATA = 17, /* data debug */ > + PERF_BR_FAULT_ALGN = 18, /* alignment fault */ > + PERF_BR_FAULT_DATA = 19, /* data fault */ > + PERF_BR_FAULT_INST = 20, /* instruction fault */ > + PERF_BR_SERROR = 21, /* system error */ > PERF_BR_MAX, > }; > > @@ -1370,8 +1376,8 @@ struct perf_branch_entry { > in_tx:1, /* in transaction */ > abort:1, /* transaction abort */ > cycles:16, /* cycle count to last branch */ > - type:4, /* branch type */ > - reserved:40; > + type:6, /* branch type */ > + reserved:38; > };
There's another copy of this struct in branch.h that is used to access the same data in perf which also needs updating:
struct branch_flags { union { u64 value; struct { u64 mispred:1; u64 predicted:1; u64 in_tx:1; u64 abort:1; u64 cycles:16; u64 type:4; u64 reserved:40; }; }; };
It's never assigned directly but there is some casting stuff going on in evsel__parse_sample() and it eventually ends up being used to access branch records. Same applies to the privilege data change.
> > union perf_sample_weight { > diff --git a/tools/perf/util/branch.c b/tools/perf/util/branch.c > index 74e5e67b1779..1e216ea2e2a8 100644 > --- a/tools/perf/util/branch.c > +++ b/tools/perf/util/branch.c > @@ -54,7 +54,13 @@ const char *branch_type_name(int type) > "IRQ", > "FIQ", > "DEBUG_HALT", > - "DEBUG_EXIT" > + "DEBUG_EXIT", > + "DEBUG_INST", > + "DEBUG_DATA", > + "FAULT_ALGN", > + "FAULT_DATA", > + "FAULT_INST", > + "SERROR" > }; > > if (type >= 0 && type < PERF_BR_MAX) >
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