Re: [RFC V1 10/11] perf: Expand perf_branch_entry.type

[Anshuman Khandual]

On 1/26/22 10:17 PM, Rob Herring wrote:
> On Mon, Jan 24, 2022 at 10:00:52AM +0530, 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@xxxxxxxxxxxxx>
>> Cc: Ingo Molnar <mingo@xxxxxxxxxx>
>> Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
>> Cc: Mark Rutland <mark.rutland@xxxxxxx>
>> Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
>> Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
>> Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
>> Cc: Will Deacon <will@xxxxxxxxxx>
>> Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
>> Cc: linux-perf-users@xxxxxxxxxxxxxxx
>> Cc: linux-kernel@xxxxxxxxxxxxxxx
>> Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>
>> ---
>>  drivers/perf/arm_pmu_brbe.c           |  7 ++++++-
> 
> This patch should come before the BRBE support so that it can be applied
> sooner rather than later. If another field is added to the end before 
> expanding this field, then you will be stuck with assembling bits from 2 
> fields.

Should I just split this patch from the series and post it separately
right away, to be included in perf while BRBE support gets reviewed ?

> 
>>  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(-)