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

[Jin, Yao]

On 7/11/2017 8:06 PM, Peter Zijlstra wrote:
> On Tue, Jul 11, 2017 at 11:00:57PM +0800, Jin Yao wrote:
> > PERF_BR_NONE            : unknown
> I would suggest PERF_BR_UNKNOWN or PERF_BR_MISC, since PERF_BR_NONE
> reads like it wasn't a branch at all.

OK, I will change it to PERF_BR_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
> >
> > The patch also adds a new field type (4 bits) in perf_branch_entry
> > to record the branch type (reserve 5 for future branch types)
> What's up with that 5 ? I can't see anything like that in the patch
> itself:

Sorry, I don't say this clearly.

We has defined 11 branch types (from PERF_BR_UNKNOWN to 
PERF_BR_COND_RET), so we can define 5 new types in future.

Thanks
Jin Yao

> > @@ -1024,7 +1048,8 @@ struct perf_branch_entry {
> >   		in_tx:1,    /* in transaction */
> >   		abort:1,    /* transaction abort */
> >   		cycles:16,  /* cycle count to last branch */
> > -		reserved:44;
> > +		type:4,     /* branch type */
> > +		reserved:40;
> >   };