Messages in this thread | | | Date | Mon, 10 Jul 2017 09:37:42 -0500 | From | Segher Boessenkool <> | Subject | Re: [PATCH v6 1/7] perf/core: Define the common branch type classification |
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Hi Peter,
On Mon, Jul 10, 2017 at 03:46:58PM +0200, 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.
If we would do that, yes :-) (We just generate a SIGTRAP instead).
> > 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.
Ah, right, exceptions == interrupts for PowerPC, more terminological confusion :-)
Segher
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