On Thu, May 16, 2013 at 1:16 PM, Peter Zijlstra <pet...@infradead.org> wrote:
> On Thu, May 16, 2013 at 08:15:17PM +1000, Michael Neuling wrote:
>> Peter,
>>
>> BTW PowerPC also has the ability to filter on conditional branches. Any
>> chance we could add something like the follow to perf also?
>>
>
> I don't see an immediate problem with that except that we on x86 need to
> implement that in the software filter. Stephane do you see any
> fundamental issue with that?
>
On X86, the LBR cannot filter on conditional in HW. Thus as Peter said, it would
have to be done in SW. I did not add that because I think those branches are
not necessarily useful for tools.
>>
>> diff --git a/include/uapi/linux/perf_event.h
>> b/include/uapi/linux/perf_event.h
>> index fb104e5..891c769 100644
>> --- a/include/uapi/linux/perf_event.h
>> +++ b/include/uapi/linux/perf_event.h
>> @@ -157,8 +157,9 @@ enum perf_branch_sample_type {
>> PERF_SAMPLE_BRANCH_ANY_CALL = 1U << 4, /* any call branch */
>> PERF_SAMPLE_BRANCH_ANY_RETURN = 1U << 5, /* any return branch */
>> PERF_SAMPLE_BRANCH_IND_CALL = 1U << 6, /* indirect calls */
>> + PERF_SAMPLE_BRANCH_CONDITIONAL = 1U << 7, /* conditional branches */
>>
>> - PERF_SAMPLE_BRANCH_MAX = 1U << 7, /* non-ABI */
>> + PERF_SAMPLE_BRANCH_MAX = 1U << 8, /* non-ABI */
>> };
>>
>> #define PERF_SAMPLE_BRANCH_PLM_ALL \
>> diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
>> index cdf58ec..5b0b89d 100644
>> --- a/tools/perf/builtin-record.c
>> +++ b/tools/perf/builtin-record.c
>> @@ -676,6 +676,7 @@ static const struct branch_mode branch_modes[] = {
>> BRANCH_OPT("any_call", PERF_SAMPLE_BRANCH_ANY_CALL),
>> BRANCH_OPT("any_ret", PERF_SAMPLE_BRANCH_ANY_RETURN),
>> BRANCH_OPT("ind_call", PERF_SAMPLE_BRANCH_IND_CALL),
>> + BRANCH_OPT("cnd", PERF_SAMPLE_BRANCH_CONDITIONAL),
>> BRANCH_END
>> };
>>
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