[PATCH v6 1/7] perf/core: Define the common branch type classification
yao.jin at linux.intel.com
Mon Jul 10 23:28:39 AEST 2017
Following branch types should be common enough, right?
+ PERF_BR_COND = 1, /* conditional */
+ PERF_BR_UNCOND = 2, /* unconditional */
+ PERF_BR_IND = 3, /* indirect */
+ PERF_BR_CALL = 4, /* call */
+ PERF_BR_IND_CALL = 5, /* indirect call */
+ PERF_BR_RET = 6, /* return */
I decide to only define these types in this patch set. For other more
arch-related branch type, we can add it in future.
Is this OK?
On 7/10/2017 9:10 PM, Segher Boessenkool wrote:
> On Mon, Jul 10, 2017 at 07:46:17PM +0800, Jin, Yao wrote:
>> 1. We all agree these definitions:
>> + PERF_BR_COND = 1, /* conditional */
>> + PERF_BR_UNCOND = 2, /* unconditional */
>> + PERF_BR_IND = 3, /* indirect */
>> + PERF_BR_CALL = 4, /* call */
>> + PERF_BR_IND_CALL = 5, /* indirect call */
>> + PERF_BR_RET = 6, /* return */
>> + PERF_BR_SYSCALL = 7, /* syscall */
>> + PERF_BR_SYSRET = 8, /* syscall return */
>> + PERF_BR_IRET = 11, /* return from interrupt */
> Do we? It does not map very well to PowerPC branch types.
>> 2. I wish to keep following definitions for x86.
>> + PERF_BR_IRQ = 9, /* hw interrupt/trap/fault */
>> + PERF_BR_INT = 10, /* sw interrupt */
>> PERF_BR_INT is triggered by instruction "int" .
>> PERF_BR_IRQ is triggered by interrupts, traps, faults (the ring 0,3
> So your "PERF_BR_INT" is a system call? And PERF_BR_IRQ is not an
> interrupt request (as its name suggests), not what we call an "external
> interrupt" either; instead it is every interrupt that is not a system
> It also does not follow the lines of "software caused interrupt" vs.
> the rest.
>> 4. I'd like to add following types for powerpc.
>> PERF_BR_COND_CALL /* Conditional call */
>> PERF_BR_COND_RET /* Condition return */
> Almost all PowerPC branches have a "conditional" version (only "syscall"
> and "sysret/iret" do not -- and those last two are the same, just like
> PERF_BR_INT seems to be the same as PERF_BR_SYSCALL).
> So how should those PERF_BR_* be used? It cannot be used in an
> architecture-neutral interface the way you define it now.
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