Re: [PATCH v7 1/7] perf/core: Define the common branch type classification

From: Michael Ellerman
Date: Wed Jul 12 2017 - 06:46:29 EST


Jin Yao <yao.jin@xxxxxxxxxxxxxxx> writes:

> It is often useful to know the branch types while analyzing branch
> data. For example, a call is very different from a conditional branch.
>
> Currently we have to look it up in binary while the binary may later
> not be available and even the binary is available but user has to take
> some time. It is very useful for user to check it directly in perf
> report.
>
> Perf already has support for disassembling the branch instruction
> to get the x86 branch type.
>
> To keep consistent on kernel and userspace and make the classification
> more common, the patch adds the common branch type classification
> in perf_event.h.
>
> The patch only defines a minimum but most common set of branch types.
>
> PERF_BR_NONE : unknown
> PERF_BR_COND ïconditional
> PERF_BR_UNCOND : unconditional
> PERF_BR_IND : indirect
> PERF_BR_CALL : function call
> PERF_BR_IND_CALL : indirect function call
> PERF_BR_RET : function return
> PERF_BR_SYSCALL : syscall
> PERF_BR_SYSRET : syscall return
> PERF_BR_COND_CALL : conditional function call
> PERF_BR_COND_RET : conditional function return

This series looks good to me, I agree with Peter that UNKNOWN would be
better than NONE.

I'll add it to my list of things we need to implement on powerpc.

cheers