Messages in this thread | | | From | Michael Ellerman <> | Subject | Re: [PATCH v6 1/7] perf/core: Define the common branch type classification | Date | Tue, 11 Jul 2017 12:28:14 +1000 |
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"Jin, Yao" <yao.jin@linux.intel.com> writes:
> On 7/10/2017 9:46 PM, Peter Zijlstra wrote: >> On Mon, Jul 10, 2017 at 08:10:50AM -0500, Segher Boessenkool wrote: >> >>>> PERF_BR_INT is triggered by instruction "int" . >>>> PERF_BR_IRQ is triggered by interrupts, traps, faults (the ring 0,3 >>>> transition). >>> So your "PERF_BR_INT" is a system call? >> The "INT" thing has indeed been used as system call mechanism (typically >> INT 80). But these days we have special purpose syscall instructions. >> >> It could maybe be compared to the PPC "Unconditional TRAP with >> immediate" where you use the immediate value as an index into a handler >> vector. >> >>> 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 call? >> It is actual interrupts, but also faults, traps and all the other >> exceptions not caused by "INT" I think. >> > Yes. It's interrupt, traps, faults. If from is in the user space and to > is in the kernel, it indicates the ring3 -> ring0 transition. > > If the from instruction is not syscall or other ring transition > instruction, it should be interrupt, traps and faults. That's how we get > the PERF_BR_IRQ on x86. > > Anyway, maybe we just use a minimum but the most common set of branch > types now, it could be a good start and acceptable on all architectures. > > 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 */
That would be fine by me, if you're sick of talking about it and just want to get it merged :)
I think you could expand it a bit, this list would cover the vast bulk of branch types for us:
PERF_BR_COND /* Conditional */ 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 */
cheers
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